If I already file my taxes but my husband hasn’t gotten his W2 and I filed jointly can he amend his W2 when he receives it

If you already filed and your spouse has not received his W-2, and the two of you want to file a joint return, YOUR return is the one that has to be amended.  Why did you file without his information?  You will have to wait for your return to be fully processed and then amend it to include your spouse's income and information.  Did you file married filing separately----or were you confused about how to file a joint return? 

A joint return is ONE tax return with all of the information for both spouses on that one tax return. The refund is one refund for both people.

When you enter your own information in Personal Info, you have to answer the question "Were you married?"  If you click the button for Married, then a drop down will appear that asks, "Do you want to file this return together with your spouse?"  Then you choose yes to file a joint return.  You would then enter your spouse's information into Personal Info.  Whenever you are entering income information there should then be a spot for you and for your spouse's income information.

The 1040X becomes available later in February, so you have to wait for it.  If your return is still being processed now, it would not be a good idea to amend yet anyhow.  Sending in an amended return while they are still processing your original return could cause confusion that would delay your refund for months.

Check back later for the 1040X.   AFTER your return has been fully processed.

How do I amend my 2019 TurboTax Online return?

A 1040X cannot be e-filed.  It must be printed and mailed.  It will take about 4 months for the IRS to process an amended return.  It is a good idea to use a mailing service that will track it, like UPS or certified mail, so you will know it was received.

Wait about 3 weeks from mailing and you can check the status of your amended return:

https://www.irs.gov/Filing/Individuals/Amended-Returns-(Form-1040-X)/Wheres-My-Amended-Return-1

https://www.irs.gov/filing/individuals/amended-returns-form-1040-x/amended-return-frequently-asked-questions

https://ttlc.intuit.com/questions/1908543-do-i-need-to-amend

https://ttlc.intuit.com/questions/3318997-how-does-the-refund-math-work-on-amendments