How to make this card have the same height in mui? I don't like setting a fixed height. This will need to change dynamically. All card heights need to be set to the highest height in the website. Between the button and the content we can add space. How do i do this?

The problem you seem to be facing is that you want to use the Material-UI library to create cards with variable content height, but you want all cards to have the same height without setting a fixed height. You also want to add space between the button and the content.

Code Sandbox

function ItemRow({ page_block }) {
    return page_block.map((page_block_item, index) => (
        <Grid
            justifyContent="space-between"
            alignItems="center"
            align="center"
            xs={12}
            sm={6}
            md={4}
            lg={4}
        >
            <Grid
                justifyContent="center"
                // alignItems="center"
                xs={10.5}
                sm={12}
                md={11}
                lg={12}
            >
                <Card page_block_item={page_block_item} key={index} />
            </Grid>
        </Grid>
    ));
}

const Card = ({ page_block_item: block_detail }) => {
    const [open, setOpen] = useState(false);
    const router = useRouter();
    const [cart, setCart] = useAtom(cartAtom);

    return (
        <Grid
            key={block_detail.id}
            justifyContent="center"
            display={'flex'}
            flexGrow={1}
            alignItems="stretch"
        >
            <Box
                sx={{
                    position: 'relative',
                    display: 'flex',
                    flexDirection: 'column',
                    height: '100%',
                    boxShadow: '0px 6px 12px -6px rgba(24, 39, 75, 0.12)',
                }}
                justifyContent="space-between"
                border="1px solid #E3E3E3"
                borderRadius="8px"
                overflow="hidden"
                margin={2}
                flexGrow={1}
                alignItems="stretch"
            >
                <Grid sx={{ position: 'relative' }}>
                    <Grid
                        item
                        position="relative"
                        sx={{ aspectRatio: '3/2', height: '100%' }}
                    >
                        <NextImage
                            className="image-cover"
                            media={block_detail.media}
                        />
                    </Grid>
                    <Box
                        sx={{
                            position: 'absolute',
                            right: 0,
                            bottom: 20,
                        }}
                    >
                        <ShareIcon
                            sx={{
                                background: '#FC916A',
                                marginRight: '15px',
                                padding: '5px',
                                height: '30px',
                                width: '30px',
                                borderRadius: '50%',
                                color: '#FFFFFF',
                                cursor: 'pointer',
                                '&:hover': {
                                    background: '#FFFFFF',
                                    color: '#FC916A',
                                },
                            }}
                        />
                        <BookmarkBorderIcon
                            sx={{
                                background: '#FC916A',
                                marginRight: '15px',
                                padding: '5px',
                                height: '30px',
                                width: '30px',
                                borderRadius: '50%',
                                color: '#FFFFFF',
                                cursor: 'pointer',
                                '&:hover': {
                                    background: '#FFFFFF',
                                    color: '#FC916A',
                                },
                            }}
                        />
                    </Box>
                </Grid>

                <Box
                    sx={{
                        flexGrow: 1,
                        display: 'flex',
                        flexDirection: 'column',
                        height: '100%',
                        maxHeight: 'fix-content',
                    }}
                    padding={2}
                >
                    <Grid item sx={{ textAlign: 'left' }}>
                        <StyledText
                            my={1}
                            variant="H_Regular_Tagline"
                            color="primary.main"
                            content={block_detail.info_title}
                        />
                    </Grid>
                    <Grid item sx={{ textAlign: 'left' }}>
                        <StyledText
                            my={1}
                            variant="H_Regular_Body"
                            color="secondary.dark"
                            content={block_detail.info_description}
                        />
                    </Grid>
                </Box>

                <Grid item sx={{ position: 'relative' }}>

                        <Link
                            href={`/${router.query.centerName}/post/donation/${block_detail?.slug}`}
                        >
                            <StyledButton
                                variant="H_Regular_H4"
                                sx={{ width: '90%' }}
                            >
                                {block_detail.info_action_button?.text}
                            </StyledButton>
                        </Link>
                </Grid>
            </Box>
        </Grid>
    );
};