Legalization proves your document is real to a foreign government. The chain depends on whether both countries signed the Hague Apostille Convention.
Apostille route (Hague members): one stamp from the designated authority in the issuing country. India's Ministry of External Affairs apostilles documents for a nominal per-document fee. One step, done.
Attestation route (non-members): a chain. Notary, then state or foreign ministry, then the destination country's embassy. Each step has its own appointment, fee, and processing time. A degree certificate for UAE employment typically goes through all three.
Sources: U.S. State Department
Consular document validation runs through apostille or full attestation depending on the destination country.
What to bring to the appointment: the original document, copies, your ID, and the fee. For consulate attested documents, every attestation step has its own appointment, fee, and processing time. What to check first: whether the destination country accepts apostilles. Half of attestation horror stories are people running the full chain when one stamp would have done.