The documents that require embassy attestation will vary based on the purpose of the visit. Commonly attested documents include educational certificates, marriage certificates, birth certificates, employment documents, and commercial documents. For example

Working Visa – You may need to attest academic documents, qualifications and criminal record checks

Spousal or Family Visa – You may need to attest marriage certificates and birth certificates

Conduction Business – You may need to provide documents confirming who owns the UK business, who operates the business and supply contracts.

*These are just examples and not advice