I had removed my phone number from my website footer, but months later it still appears once I look it up on google, how to remove it?

It usually takes several days (or more) for search results to be updated.

First step would be to look at every single page of your site and check for the correct phone number.

Then create a new sitemap.xml file, and submit that to the various search engines (like via Google Webmaster Tools). Many articles available on how to do that. There are even sites that will analyze your site to create a sitemap.xml file.

Once you submit the new sitemap.xml file, you will have to wait for indexing to be updated. That may take a week or more, so ‘patience, Grasshopper’.

(Note that your question is not related to WordPress development, so it may be closed to accepting additional answers.)