Its app icon resembles a white "W" on a dark-blue background. It's in the upper-left side of the window. Doing so will open a new Word document. This tab is in the blue ribbon that's at the top of the Word window. Doing so opens the Mailings toolbar below the blue ribbon. It's in the "Create" section of the toolbar, which is on the far-left side of the window. Click the text box below the "Delivery address" heading, then type in the address to which you want to send your envelope. Make sure that you type the address exactly as you want it to appear here. Click the text box below the "Return address" heading, then type in your return address. Again, this must be typed exactly the way that you want the address to appear on the envelope. It's near the bottom of the window. A new window will open. This option is at the top of the window. It's near the top of the window. A drop-down menu will appear. Click the size of your envelope in the drop-down menu. It's at the top of the window. Click one of the visual representations of an envelope feeding into a printer. This is how you'll need to insert the envelope into the printer. It's at the bottom of the window. If you haven't yet connected your printer, do so before proceeding. Make sure that you do this according to your chosen feed format. It's in the bottom-left corner of the Envelopes window. Your envelope will begin printing. If you encounter issues while printing the envelope, try resetting the feed format to the Word default.

Summary:
Open Microsoft Word. Click Blank document. Click the Mailings tab. Click Envelopes. Enter a delivery address. Enter a return address. Click Options…. Click the Envelope Options tab. Click the "Envelope size" drop-down box. Select an envelope size. Click the Printing Options tab. Select an envelope feed format. Click OK. Make sure that your printer is on and connected to your computer. Place the envelope in your printer. Click Print.