It’s a disingenuous question: the answer is obviously yes. Consider, though, how often you write one when you might not need to, and whether a reader might be able to extract the necessary information more quickly.
(No shade meant to the paragraph. I love paragraphs.)
| I’m explaining how to do something. | Use a list of steps. |
| I’m persuading someone to do a thing. | Sure, you can use a paragraph–also consider bullets, or a table. |
| I’m creating reference information. | How about a table or diagram? |
| I’m teaching someone a skill. | OK, but maybe give them hands-on activities? |
| I’m clarifying how something works. | Maybe, but diagrams are good too. |
| I’m explaining why something does something. | Go for it! Paragraph! |
| I’m describing something. | OK, but: 1. Make sure you have a good reason to describe it at all! 2. Would a picture or diagram help reduce paragraphiness? |
| I’m describing a user interface. |
You poor thing. Here is some whiskey. Please don’t write paragraph-length descriptions of a UI. If you can’t have screenshots (lots of reasons why not), your UI is truly baffling, and the UI team can’t incorporate field descriptions on screen, how about a definition list or table? |