You can apply for either an HDB Loan Eligibility (HLE) Letter from HDB or a Letter of Offer from a bank or financial institution. For an HDB housing loan, the amount depends on factors such as the remaining lease of the flat, your current age, and a maximum repayment period of 25 years. If you are taking a bank loan, you need to check the total debt servicing ratio (TDSR) and loan-to-value (LTV) limits set by the Monetary Authority of Singapore (MAS). Both approaches require reviewing your monthly income, outstanding mortgages, and meeting any applicable age and property criteria.