Highend Options Not Saving

I am trying to change some settings within my website by adding social media icon (instgram) and removing the search from the header.

When I change anything and try to save, it just says “Saving Now” and takes forever, I’ve left it going for a long time but with no luck.

i have read from other topics that i need to extend my wp memory limit but i have no idea how to do that even with this link.
https://hb-themes.com/forum/all/topic/how-to-increase-max_execution_time-variable/

please Help its very urgent.

Thank you and HAPPY NEW YEAR