Are you trying to transfer 2024 into 2025? If you used the Desktop program last year you should have the file ending in .tax2024 on your computer. You can transfer it into the Online version but you have to do it by logging in to online from your computer. Then you can switch and log into the table.
How to Transfer into the Online version
https://ttlc.intuit.com/turbotax-support/en-us/help-article/import-export-data-files/transfer-last-y...
