Yes, but unless it gets posted as a 2020 contribution by the financial institution it won't count for 2020. Many, if not most, financial institutions take up to 3 business to post a contribution so it would be a 2021 contribution. Ask you financial institution if they will allow it.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**