A relatively new feature introduced in macOS Sierra allows you to insert a period by double-tapping the keyboard. This will work in any application that accepts text entry (or at least it worked in all the ones I tested). You can already do this in iOS but it was only recently introduced into macOS. Many people aren’t even aware that this feature exists because it is turned off by default, unless you’ve installed a fresh version of Sierra or High Sierra (or purchased a new Mac).
You can turn on the feature from the Text tab of the Keyboard Preferences pane.
Quick Guide: Automatically Add a Period with Double-Space
- Click Apple > System Preferences.
- Click the Keyboard icon.
- Click the Text tab on top of the window.
- Click the checkbox next to Add period with double-space to check it. To turn off the feature, click the checkbox to uncheck it.
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