You are smart to wait until you get all your W-2s before filing. Not waiting can cause a lot of trouble.
Your employer is required to send you a W-2 in a timely manner (before the end of January). If an employer does not, please see IRS Can Help Taxpayers Get W-2. Note that this was written for tax year 2018, but the information is still substantially valid.
The same is true if the other "employers" actually owe you form 1099-MISC for contract work.
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