Some preferences can be found in this folder:
But I don't think you can export most preferences, so take screenshots of the Preferences windows before formatting your hard-drive, just in case...
Regarding signatures: It depends on the type of signature.
Some signatures are just stamps, for example those that can be created via the Sign panel on the right. You will find them in the following path:
Other signatures (digital IDs) can be exported by going to Edit - Preferences - Signatures, then click the More... button in the Identities & Trusted Certificates box and from there you could export the digital IDs in your computer as files.
Which version of Acrobat are you using? In Acrobat 9 and later you can export security setting to a file and then import them on another machine. You will need a signing credential to certify the security settings file as this feature requires that the security settings file is certified.
In Acrobat X it is under Tools->Sign&Certify->More Sign&Certify->Export Security Settings
In Acrobat XI it is under Edit->Preferences->Security->Export
On a separate machine you use the same place but select Import.
I commonly use set certify in all my learning practices online cause I'm out off school not residing in auSA that's why I performed all the role requires that should be in a group or a team I did that just to save the role that had been given to me I don't want adobe system to go to waste it takes a out way learning just to end up orbit my plan is test all thetri it and istriute it