Good morning,
First of all, to avoid future problems, I recommend you to check if the plugin you are going to install is compatible with your WordPress version and with the PHP version you are using.
To solve this you will need to have access to the hosting where the website is hosted. Most web hosts use cPanel, so I am going to explain it assuming you use cPanel.
You must access cPanel, if you don’t know how, you can talk to your hosting provider’s support.
Inside of cPanel there is an option called ‘File Manager’. Once you are in, locate the ‘public_html’ folder and then the ‘wp_content’ folder. Look for the ‘plugins’ folder. Here you can see all the plugins installed on your website. Just delete the folder of the plugin that caused this problem. If you don’t know the name, you can filter the results by the date of the last modification. You must match the creation date of the folder with the time you installed the plugin (approximately).
Hope it helps!
Have a good day ??
