The computer can check grammar in the same way.

If there is a check in this box, the computer will also look for grammar mistakes.

If you do not want this, click on the box and the check will go away.

Then the computer will search for spelling mistakes only.

Warning!
The computer can miss many mistakes.

Example:
I go to work at mine o’clock.

Nine is spelled wrong but it looks the same as the word mine, so the computer will not find the mistake.