It’s easy! You may send a message to anybody on Instagram through Direct Message, be the account private or open. If the other individual doesn’t follow you, they will get your message as a request, which when accepted shall continue as inbox messages over the platform.
Once you have 10k followers, Instagram will make it easier for you to get people to your website via Stories with the swipe up to link feature. Swipe up is the only way to get a direct link from your Instagram to your other web properties. And, it’s available in STORIES, if you have 10k followers.