If you want to "edit" a PDF, then Claude Sonnet works well, although what it's going to do is regenerate it from scratch trying to retain overall formatting. It can even do this for scanned PDFs and foreign language ones that need translating.

If you just need to create PDFs, not edit them, then Gemini notebook (notebook.google) works well and has Google's usual very high free usage limits.

AFAIK in general you can't really edit PDFs since it's not a reflowable format - even with Adobe tools all that editing does is modify the text within a text box - not reflow the document to adjust to any change in size of the text box.

You probably mean 3.5-flash? Pro is still good for a lot of use cases, but it seems it's still officially in the "preview" phase.

3.5 pro doesn't exist yet?