The information is hidden in different documents, so the statement "no documents is required" is wrong. We don't need to send the evidence documents but we do need to include a copy (front and back) of your last available TPS document: EAD, Form I-94, or approval notice. And yes we will have to go for another bio-metrics as we will be paying for it during re registration.

Citations:
B.Documentation exception: If you are filing this application for re-registration (
Part 1., Item Number 1.b., of Form I-821), you do not have to submit any copies of documentation. However, USCIS may ask you for additional information and/or documentation in certain circumstances.
7. Will TPS applicants need to provide fingerprints and photographs?
A. Yes. Except as noted below, all applicants for initial registration, re-registration, or renewal of TPS must provide fingerprints, photographs, and signatures, which are biometrics. Applicants 14 years of age and older must submit the $85 biometrics services fee or a fee waiver request. See Item Number 9 below for information about fee waiver requests.

C. Temporary Protected Status (TPS)--(a)(12) and (c)(19). A category (a)(12) EAD is issued to an individual granted TPS under 8 CFR 244. A category (c)(19) EAD is a temporary treatment benefit under TPS pursuant to 8 CFR 244.5.
To request an EAD based on TPS, file Form I-765 with Form I-821, or with evidence that your initial Form I-821 was accepted or approved. Include evidence of nationality and identity as required by the Form I-821 instructions. If you are requesting extension of TPS status, also include a copy (front and back) of your last available TPS document: EAD, Form I-94, or approval notice.