Write an article based on this "Open the Google Docs app. Open the document in which to add double spacing. Tap the editing button. Highlight the text you want to double-space. Tap the editing menu. Tap the PARAGRAPH tab at the top of the menu. Set the line spacing to 2.00. Tap anywhere on the document."
It's a white app with a blue paper icon that contains white lines.  It's a blue circle with a white pencil icon in the lower-right corner of the screen. Use your finger or the arrow buttons on a hardware keyboard to do so. Long-tap the text and tap Select all to select all the text in the document. It's an A with horizontal lines in the upper-right corner of the screen.  Tap {"smallUrl":"https:\/\/www.wikihow.com\/images\/1\/1e\/Android7expandmore.png","bigUrl":"\/images\/thumb\/1\/1e\/Android7expandmore.png\/30px-Android7expandmore.png","smallWidth":460,"smallHeight":460,"bigWidth":"30","bigHeight":"30","licensing":"<div class=\"mw-parser-output\"><p>I edited this screenshot of an Android icon.\n<\/p><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/en.wikipedia.org\/wiki\/Fair_use\">Fair Use<\/a><br>\n<\/p><\/div>"} or {"smallUrl":"https:\/\/www.wikihow.com\/images\/7\/70\/Android7expandless.png","bigUrl":"\/images\/thumb\/7\/70\/Android7expandless.png\/30px-Android7expandless.png","smallWidth":460,"smallHeight":460,"bigWidth":"30","bigHeight":"30","licensing":"<div class=\"mw-parser-output\"><p>I edited this screenshot of an Android icon.\n<\/p><p>License: <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/en.wikipedia.org\/wiki\/Fair_use\">Fair Use<\/a><br>\n<\/p><\/div>"} on either side of the number to increase or decrease it to 2.00. The highlighted text is now double-spaced. While different paragraphs may have different spacing, all the lines in a single paragraph must maintain the same line spacing.