This blog describes how to create and add SPFx app as Teams Tab. Also, this blog is with respect to SharePoint framework version 1.7
Create your SPFx web part, After you are done with development, deploy it
Add the package to your App catalog
Now in your web part, go to Teams folder.
In Teams folder, there will be 3 files (manifest.json, tab20*20.png and tab96*96.png)
Zip the 3 files in Teams folder, make sure your zip file doesn’t contain any folders in it.
Now go to respective team of site in teams, go to General -> Click on + ->Manage Apps -> Upload a custom app -> and upload the zip file which you created earlier
That’s it
Your app will be added as teams tab
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