So you just got your guest log drawing in the mail (or it is on its way and your thinking ahead). It is fresh and clean and empty, ready for your loved ones to fill up.
For your guests to sign over or next to their prints, any archival, fine art or scrapbooking pen will be good. Just dont use regular or fine point sharpies. Here are some pens that are BDT approved (from high to low in price)
Fine art drawing pens:
Copic Multiliner SP in .3
Faber Castell Black Superfine nib
Micron Pen in Black Size 03
Memory Marker, two sided F and M in Limo Black
Precision Pen .03 point in black
Zig Memory System Millennium Pen in .03
Point 88 Fineliner Pen in black, also come in an array of colors
On the big day, I suggest having a white box (or two if you are having a big crowd) of baby wipes on hand at the table with the guest log, so that the guests can wipe the ink off of their fingers before signing their name, and before it dries. It looks nicer if you peel the stickers off and is helpful if you cut the wipes in half ahead of time so they arent huge pieces.
Finally, framing before or after the event is up to you. If your ordered a medium drawing or smaller, it might be ok for it to be unframed on a table top. For a larger piece you might want to have it dry-mounted at your local framer or place it in a frame without the glass, so it keeps the edges safe and provides a hard surface beneath it. A piece in a frame is nice to display on a sturdy easel sometimes.