For those of you using Bigger Pockets' leases - How do you edit them?

[Julie Kuczmarski]

Hi. I purchased the NC lease from Bigger Pockets. Overall, I am very happy with it, but would like to make a few small changes to it. My question is what programs or software do you use to make changes to the document. I would prefer to work with the fillable pdf document  if possible, but have been unable to make any changes to it at all. TIA for your help.