Hello I have acrobat DC, I have signed in with my adobe ID but I cannot edit,convert pdf. Please advise. I have my serial number as well

Let's find out what the software thinks it is. Please go to the Help menu in it and look for the first About entry. Does it say About: Adobe Acrobat DC, Adobe Acrobat Reader DC, Adobe Acrobat Pro DC, Adobe Acrobat Standard DC, or something else. Please give the exact text you find.