You have several options for migrating from on premises SQL Server to Azure SQL Database. The main ones are:
- the Azure SQL Migration extension in Azure Data Studio - I believe this is the currently recommended option but from experience I can tell you it doesn't handle schema or data type changes well
- Azure Migrate
- Azure Data Factory - this is the best option I've found if you have schema changes
However for all options, you'll want to time them to determine if they're fast enough for your requirements by testing them.
If you have tight deadlines in which to do the upgrade, e.g. a short maintenance window on a production application database, you could also consider transactional replication as this would allow you to minimise the time taken to switch from on premises to Azure.
Microsoft has a comprehensive Migration guide which covers a number of options, considerations & limitations.