Any format is OK!
Metadata guidance from CDISC is a good way to go.
https://wiki.cdisc.org/download/attachments/113589261/aCRF_Guideline_v1-0_20201120_publish.pdf
The by Sergiy mentioned document is not from CDISC.
It is a private initiative from a number of people in Germany.
If you want guidance from CDISC, then use the Metadata Submission Guidelines v.2.0. You can download it from:
Is the annotated CRF (aCRF) used in submission required to be the one pulled out from EDC and annotated manually, or is any format of an aCRF fine as long as it includes all the annotations supporting the tabulation datasets and define file?