Hello mimi1954 and welcome to the HP forums!
I see that you're having issues printing because your printer is offline. I will certainly do my best to help you get it back online, I just need to gather a bit more information first :)
1. Which model HP printer do you have?
2. Which version of Mac or Windows do you have?
3. Is the printer connected via USB or wireless?
4. Where are you seeing that the printer is offline?
5. Have there been any changes to anything in your setup recently?
Once I have this information I can have a further look into your issue!