The Office apps for mobile devices automatically set a default margin around each page. In Word, you can easily choose a different margin from the gallery, which changes how much white space borders the text or other content in your document. In PowerPoint, you can change the margins by adjusting the height or width of a text box. You can't, however change the margins in Excel.
:Â You can't create custom margins in Office apps for mobile devices.
On your Android tablet or phone
:Â Custom margins is available only for Office Insiders. This feature is only available to Microsoft 365 subscribers who have joined the Office Insider program. If you are a Microsoft 365 subscriber, make sure you have the latest version of Office.
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On your Android tablet, tap Layout. On your Android phone, tap the Edit icon
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On the Layout tab, tap Margins.
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Select a margin from the drop-down gallery. Each selection shows the margin measurements.
To set margins for facing pages, select Mirrored from the drop-down list.
To set your own margins, select Custom Margins from the drop-down list and specify the Top, Left, Right, and Bottom margins measurements.
In PowerPoint, you can change the margins by changing the size of a text box. Tap the text box, and then use the handles 
You can't change the margins in Excel Mobile for Android tablets or phones.
On your iPad or iPhone
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On your iPad, tap Layout. If you are using an iPhone, tap the Edit icon
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On the Layout tab, tap Margins.
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Select a margin from the drop-down gallery. Each selection shows the margin measurements.
To set margins for facing pages, select Mirrored from the drop-down list.
To set your own margins, select Custom Margins from the drop-down list and specify the Top, Left, Right, and Bottom margins measurements.
In PowerPoint, you can change the margins by changing the size of a text box. Tap the text box, and then use the handles 
You can't change the margins in Excel Mobile for iPad or iPhone.
On your Windows tablet or phone
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On your Windows tablet, tap Layout. If you are using a Windows phone, tap the ellipsis
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On the Layout tab, tap Margins.
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Select a margin from the drop-down gallery. Each selection shows the margin measurements.
To set margins for facing pages, select Mirrored from the drop-down list.
To set your own margins, select Custom Margins from the drop-down list and specify the Top, Left, Right, and Bottom margins measurements.
In PowerPoint, you can change the margins by changing the size of a text box. Tap the text box, and then use the handles
You can't change the margins in Excel Mobile for Windows 10 tablets or phones.
