For 2020 I received three W2's. I accidentally only filed 1. My return was accepted on 2/10/21. I have not received my refund. Can I file an amended return now for 2020?

I e-filed one W2 for the 2020 tax year. That one W2 was accepted on February 10th, 2021. It still is processing on the IRS site over a month later. Since it was accepted, can I go ahead and file the amended return for the other two W2s I missed? And if so, can this be done electronically? Thank you!