Hello anitastacey,
Thanks for choosing the Apple Support Communities. It sounds like one of two things may be wondering your ability to open social media on your iPhone. Either you have restrictions turned on that don't allow it, or you have a configuration profile installed that may be hindering the ability to access those websites. Below are resources on each. Check both, and see if turning off restrictions or removing any configuration profiles may resolve the issue.
Use parental controls on your child's iPhone, iPad, and iPod touch - Apple Support
"Prevent web content
iOS and iPadOS can automatically filter website content to limit access to adult content in Safari and other apps on your device. You can also add specific websites to an approved or blocked list, or you can limit access to only approved websites. Follow these steps:
- Go to Settings and tap Screen Time.
- Tap Content & Privacy Restrictions and enter your Screen Time passcode.
- Tap Content Restrictions, then tap Web Content.
- Choose Unrestricted Access, Limit Adult Websites, or Allowed Websites.
Depending on the access you allow, you might need to add information, like the website that you want to restrict."
Install or remove configuration profiles on iPhone - Apple Support
We hope this helps.
Cheers!