How to install cocoapods on mac?

Question

macOS

Trying to install cocoapods on macbook. Trying to do this with sudo gem install cocoapods gives the error
Successfully installed activesupport-5.2.4.4
Building native extensions. This could take a while...
ERROR: Error installing cocoapods:
ERROR: Failed to build gem native extension.

current directory: /Library/Ruby/Gems/2.6.0/gems/ffi-1.13.1/ext/ffi_c
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby -I /System/ Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0 -r ./siteconf20201114-22919-9ybr68.rb extconf.rb
checking for ffi.h... *** extconf.rb failed ***

Tell me, please, how to fix it?