When you choose asset in FileMaker get started, in check out you will have a signature button in Asset Details|iPad and you can sign the gotten asset.
How can we sign it by fingerprint?
You might research 'biometric filemaker' here and via your favorite search engine.
I have to use plug-in?
Or it can be done without it?
In FM Go it works natively with Touch ID if you set it up correctly but that wouldn't apply to one device having to cater for many users checking out equipment.
So yes: you'd need a plugin. And you'll need to register all fingerprints ahead of time which may be prohibitive...
How can I have a biometric plug-in in my iPad that the FMG works on it
Plug-ins do not work in FMGo.
As stated by Wim Touch ID does work with FMGo.
See setting File Options in FileMaker Pro 16 Help
File>File Options>Under the Open Tab is 'Allow Credential Manger to save password' After that is checked then there is an Option to 'Require ios Passcode'. Select both these options.
Retrieving data ...