simple htmp post-get (noob question)

i'll looking for a snippet of code in php to post a set of variables to a url and then display the return data. example:

&field1=a&field2=b&field3=3

https://www.example.com/dir/

i searched for a few hours and cannot put the code together. most of the php sites talk about post and get functions, but i cannot find a good, rather working, example. do i need two php pages, one to call the other? do i use html form submit? what tells the page to just display/print the response. i'm sure i can figure out how to parse the info but i'm stuck on first step, post-get data. thanks in advance!