This form is sent by the Marketplace to everyone who has medical insurance through the Exchange (Obamacare).  It contains necessary information needed to complete your return.  If you, your spouse, or any dependent had this insurance for even one month in 2020, this information must be included.  Filing a return without this information will cause the IRS to suspend processing the return.  They will then send a letter indicating the missing information with instructions on correcting the problem.