If your WordPress-based website is showing a blank or white screen, check this video:
For other types of websites, the most common reason for a blank page is code-related; for example, there may be a character missing somewhere (such as a semicolon, a quotation mark or a bracket). In those cases, instead of an error message, the website will simply show a blank screen.
To identify the cause and troubleshoot it, you can try the following suggestions:
Enable PHP error reporting: You can get more information by checking any error messages PHP may show. For security reasons, error display is disabled by default - to enable it, follow these steps: How to turn on PHP error messages in hPanel?
Test your code often: Testing each piece of code as you add it will help you identify an error more quickly - it is likely related to the most recent changes applied
Try a color-coded editor: Color code will make lines that don't end properly stand out better since you'll see large parts of code in the same color. There are free editors available that include this feature
Comment out code: One more way to isolate the issue is by commenting out portions of your code. Starting at the top, comment out all but the first couple of lines, then add an echo() test message right above the commented code.
If the echo displays correctly, the issue will be below. Move the start of your comment and your test echo downwards as you work through until you find the root cause of the blank page
If you need the help of a developer with this issue, you can consider the options available on Fiverr