我強烈建議使用更多變數。您的程式碼可能如下所示：

// Height is different in multicell, this stands for lineheight and should be the same as other cells :)
// I would advise you to go for, SMALL_CELL and BIG_CELL if you want to differentiate
$WIDTH_CELL = 60;
$HEIGHT_CELL = 5;

// Most of the time, you want to border all so let's put this in a variable as well 
// Not in your case though, but more on that below this :)
$BORDER = 1;

$pdf->Cell($WIDTH_CELL, $HEIGHT_CELL, 'MAILING ADDRESS', $border, 0);
$pdf->Multicell($WIDTH_CELL, $HEIGHT_CELL, $puchaser1[0]["address"], $border);
$pdf->Cell($WIDTH_CELL, $HEIGHT_CELL, $puchaser2[0]["address"], $border);

$pdf->Cell($WIDTH_CELL, $HEIGHT_CELL, 'PHONE NUMBER', 1, 0);
$pdf->Cell($WIDTH_CELL, $HEIGHT_CELL, $puchaser1[0]["contact_no"], $border, 0);
$pdf->Cell($WIDTH_CELL, $HEIGHT_CELL, $puchaser2[0]["contact_no"], $border, 1);

但是，這不能解決您的問題。你將會度過一段糟糕的時光，因為你需要：

1. 追蹤您的起始 Y
2. 新增多單元格後儲存 Y 值
3. 使用這兩個值為整行繪製一個矩形

所有其他邊框應具體為「L」、「R」或「LR」。您必須用矩形繪製頂部邊框、底部（有時是 L 或 R）邊框。

程式碼很多，所以如果您有這樣的程式碼，我會進一步幫助您:)