A dated copy of the official program terms as they stood when each decision was taken, together with a record of where it was obtained. Beyond that, identify the applicant, the payer and every family member to be included, and keep the payment records and vetting correspondence in a single chronological file.
Undated screenshots are the weakest thing in most files
Programs that are still being implemented change, and advice given in good faith six months ago can be wrong today. The discipline that protects Rashid is unglamorous: whenever a material decision is made, capture the official page or notice with the date and the address it came from, and file it. If the terms later change, the file shows what was relied upon and when, which makes it possible to reassess rather than argue.
Alongside that, keep the identity documents for each person to be included, evidence of the relationship for a spouse or child, and the corporate documents if a company is the sponsor, since the sponsoring entity's identity and its relationship to the applicant will be examined. Keep payment confirmations with the instruction that authorized them. What should not be in the file is a comparison chart from a promoter presented as though it were the program's own terms.