I ran into the WordPress error while adding a new plugin from the WordPress Repository:
The plugin does not have a valid header.
With little to no advice or tips online, I decided to piece together a short article to help people experiencing the same issue.
How to fix: The plugin does not have a valid header.
Install the Plugin
First, you will need to attempt to install the plugin.
Try to Activate the Plugin
Once installed, try to activate the plugin. As you already know, this most likely will not work, but it’s crucial to try in case it’s an intermittent issue.
When it fails
When the plugin fails to activate, go to the Installed Plugins page. You will be able to start the plugin from that page.
You can find the setting under the plugins toolbar on the left hand side.
I hope this helps fix your plugin problems; if you have anything to add, please comment below.