Banks like to be sure that someone or something will pay them back. That is why they want assets in place of the loan.
With a home loan, the home itself is the asset they hold. Same for cars and bikes.
But with education, that is not possible.
Hence, they want collateral, such as a house or non-agricultural land.
In case you default, they would sell off the asset and recover the investment.
Which collateral do they like most? A fixed deposit of the amount they are loaning out.
They can access it with no problem, and the cost of liquidation of assets is minimal.
Banks like to call a guarantor a co-signer.
A co-signer is usually a person who is a relative (parents, parents-in-law, or spouse) and promises to repay the amount due if you default.
Of course, they need to show a source of income that would allow them to do so.
Banks would want collateral, a guarantor, or both, depending on the case.
Every bank has separate criteria in this matter.