Mbstring stands for multi-byte string functions. Mbstring is commonly used PHP extension and is required for our PDF and Email Extension to function properly. If mbstring is not enabled on your server, you may experience problems like blank pages (instead of the PDF file you expected), or emails that don’t send.
Fortunately, however, mbstring is easy to enable. In most cases, a simple phone call or email to your web host is all that’s required and they will be happy to enable it for you.
If you have cPanel hosting and want to try it yourself, you can enable mbstring by doing the following:
How to Enable mbstring in cPanel
1) Login to cPanel.
2) Go to the section ‘Software’.
3) Click the icon ‘Select PHP Version’
4) Select the php extension ‘mbstring’.
5) Click the button ‘Save’.
For other servers / hosting situations, the best advice is to contact your host directly.