how to remove a hard return

What is the command for removing a hard return? I want to know how to remove a hard return in a document or an email (I’ve tried both Word and my email). I'm new to Mac but on my PC I usually just put the cursor to the right of the last letter on the line and hit delete and the line below gets moved up but in the MAC when I do that all it does is delete the letters in the word to the left of the cursor.

Thanks.