Website bookmark doesn't have a "remove bookmark"option

1. Is this your corporate iPhone? Then please contact the system administrator of your corporate
2. If it is your personal device, in that case, do you have any profile installed by your corporate/organisation/enterprise/School Management?
   1. Erase the profile added by you If you have installed a profile on your own --> Install or remove configuration profiles on iPhone - Apple ...
   2. Or please contact the system administrator of the organisation who provided the profile to you

If your iPhone is managed / administered by an Organisation / Corporate / enterprise and if they have installed Device Management Profile then these links will help you.

If your iPhone is individually owned and you have installed an app which prompted you to install a profile then these may help you.

Otherwise these will be for academic purposes only

Get started with a supervised iPhone, iPad, or iPod touch - Apple ...

Get started with a supervised iPhone or iPad - Apple Support

Install a configuration profile on your iPhone or iPad - Apple Support

Install a configuration profile on your iPhone or iPad - Apple Support

The pic below is self-explanatory

First disable the Screen Time Restrictions, if any.

Settings > Screen Time > Contenet And Privacy Restrictions > iTunes & App Store Purchases > Deleting Apps > [Allow]

There are six possibilities

1. Delete an offloaded App
2. Delete an App from the Home Screen
3. Remove an App from the Home Screen - Will be placed in the App Library
4. Delete an App from the App Library
5. Delete an inbuilt App - Not feasible
6. Delete an inbuilt App with one feature - You do not get any options either (e.g. Magnifier)

Watch the GIF

To improve understanding of the phenomenon, it would be highly beneficial if you could share a screenshot. Visual representations carry greater impact than written descriptions.

Please remember that this is a public forum, so when attaching a screenshot, please avoid including any personal credentials such as IP addresses, card details, email IDs, Apple IDs, IMEI numbers, serial numbers, phone numbers, order IDs, or any identifiable location information if you are sharing a map.

With the limited information that you have provided, It is hard to even guess the problems faced by you. 

You may get faster and better responses to your query by --> Writing an effective Apple Support Commun… - Apple ...

Please re-post with detail so that someone else can help.