Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
If this is Word for Windows, you can click at the very left of the cell contents and use Shift + Right arrow until the whole cell becomes selected:
Then click the arrow on the border button in the Paragraph group on the Home tab and click Borders and Shading. Go to the Shading tab and choose the desired options. Make sure that "Apply to" is set to "Cell."