How do I stop text from deleting when I try to insert letters and new words?

I am writing as usual but the cursor has changed and when I try to add or change a word the next letter deletes there is a black flashing box behind each letter. How do I remove the problem?

Check in the status bar (bottom of window) if it displays “OverWrite”.

If this is the case, press Ins key to switch from “overwrite” to “normal” text entry.

To show the community your question has been answered, click the ✓ next to the correct answer, and “upvote” by clicking on the ^ arrow of any helpful answers. These are the mechanisms for communicating the quality of the Q&A on this site. Thanks!

In case you need clarification, edit your question (not an answer) or comment the relevant answer.

Just press Insert

See this field on Status Bar

InsOver.png