I have an existing database using PHP, MySQL and phpMyAdmin.
When users become a member on my website, I need the system to create a unique membership number for the
This is due to the wp_terms, wp_termmeta and wp_term_taxonomy tables, which had all their ID's not set to AUTO_INCREMENT
To do this go to phpmyadmin, click on the concern database, wp_terms table, click on structure Tab, at right side you will see a tab named A_I(AUTO_INCREMENT), check it and save (You are only doing this for the first option, in the case wp_term you are only doing it for term_id).
Do the same for wp_termmeta and wp_term_taxonomy that will fix the issue.