can't fill out pdf in Preview

Wow, I used to be able to date and sign purchase orders in Preview. I got a new computer for Christmas (El Capitan) and now I can't get it to work anymore. When I click on the line where I need to type in the date, I get a text box that is long but not very tall at all. When I type, nothing appears. I cannot resize the text box in any way.

I can still add my signature, but it imports huge and has to be resized and positioned every time now (it used to automatically size to fit the signature line when I clicked on the line).

Doing this used to take less than :60. Now it takes 15 minutes because every time there's a new hurdle, it seems and I end up going on the Internet to find a solution.

Does anyone know if El Capitan "broke" this feature, or am I just doing things wrong? If it's broken, I'll pay for Acrobat Pro I guess, because I use this feature on pretty much a daily basis and I can't take the time to sort it out every time.... This used to be a great feature, and it was free.

Thanks for any help.