Step 2. Click the spot in the document where you want to insert the check box. Step 3. Click the âCheck Box Content Controlâ button in the âControlsâ group. This button displays a check mark inside a check box. The check box appears on the document.Step 4. Click the âRestrict Editingâ button in the âProtectâ group. To insert a check box for a printout, click the âInsertâ tab. 2  Click the arrow for the âSymbolâ button in the âSymbolsâ group. 3  Click âMore Symbols.â A gallery of symbols appears. 4  Click the preferred symbol.