The IRS started processing tax returns on January 29th, which is much later than previous filing seasons, and they have a large accumulation of tax returns to process.
After your refund has been accepted, it will typically be issued within 21 days.
After your return has been successfully transmitted, then it will be accepted, processed, and approved. After the approval stage, your refund will be issued.
If your tax return has been accepted and you have checked Where’s My Refund, and haven’t seen a status update, that is typical because the IRS won’t have record of the return until it is in the processing stage, so no need to worry.