1, you can consider using photoshop or the "drawing" program that comes with windows to sign with the mouse, but countersigning is not good.
2. Sign your name on a piece of white paper, take a photo or scan it into a picture file, then use photoshop to process it into an independent name with a transparent background, and then insert it into a pdf file as a picture. As for how to insert, one can convert pdf into word before inserting, and the other can use special pdf editing software. As for the date, acrobat can enter it directly.
3. It is normal and simple to print out the pdf file, hand-sign and date, and then fax it to the other party, or take photos, scan it and turn it into a pdf or picture file and send it to the other party by email.
I suggest you adopt the third option.