What does it mean that my return has been accepted

[VolvoGirl]

Accepted only means the IRS verified some basic info on it so they know it's really from you.  After it is Accepted the IRS processes it then approves it before they send the refund.

What does Accepted mean

https://ttlc.intuit.com/community/return-status/help/what-does-accepted-mean/01/26285

[Texas Roger]

Accepted means your tax return passed initial screening of SSN, name and SSN match, whether or not anyone else claimed you on a tax return, etc.  It usually takes from 24-48 hours for a return to be accepted after it is submitted to the IRS.

After it is accepted, the IRS begins processing your return to make sure it is correct based on their information and to see if any offset should be applied. That can take from a few days to months. In normal times, most returns are processed within 21 days. But there is currently a huge backlog of unprocessed returns. 

If you are getting a refund, you can track it on the IRS tracking web site: https://www.irs.gov/refunds

See this IRS Q&A about the process: https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions