The easiest, but least effective, way is to send an email to President@whitehouse.gov or go to this web page:
However, this email box gets lots of emails daily, and you are likely to get a "form" reply.
A more effective approach is to actually email the specific person who is responsible for the topic you want to write about. That person will be more likely to read and follow up on your email.
The most effective approach is to apply some political pressure so that your email is read and acted upon. If you can use a lobbyist or a politician to pass your message along then you can get towards the top of the queue.
Related Q&A:
What is the email address for the White House?-Well, the email address for the White House can change over time, and it's best to get the most up-to-date information from the official White House website. But as of my knowledge, you might try something like president@whitehouse.gov or comments@whitehouse.gov. However, keep in mind that these might not be the exact ones, and it's crucial to double-check on the official source to ensure you have the correct and current email address. Oh, and make sure your communication is respectful and relevant when reaching out!