Although Google Docs is a web application and can be accessed through different operating systems, the process for selecting multiple groups of text differs based on the type of system a person is using. For Windows and Chrome OS users, select the first portion of text normally. Then, use the keyboard shortcut Ctrl + Alt + Shift + Left/Right Arrow to trigger the multiple text-selection user interface and move the left or right arrow to the other portion of text to be selected. On Mac, the keyboard shortcut is different. After selecting the first portion of text, pressing Ctrl + ⌘ + Shift + Left/Right Arrow triggers the multiple text-selection user interface, and users can then move to the other portion of text to be selected.
The new feature might take a little time to get used to, but can be a game-changer for casual users and power users alike. It should reduce formatting times considerably, as the previous implementation of text selection required users to individually format each desired portion of text. Now, text scattered across a document can be changed at once. For example, if a user wants to increase and bold the font of titles or subheadings throughout a document, they can select and change these portions in one action. In doing so, the text and other elements in between the titles and subheadings are left unchanged. Depending on the document, this could save a massive amount of time that would have been wasted on tedious formatting. It’s a relatively simple feature addition, but its presence increases the flexibility users have when formatting a document in Google Docs.
Source: Google Workspace