You will find below the steps to follow in order to become opt-out on the web depending on the browser you are using.
In order to opt-out, you will need to go to your browser settings > Advanced > Clear browsing data.
Then access the Browser Settings > Advanced > Content settings > Notifications > Click on the 3-dot-icon of the websites you want to opt-out from > Click Remove
You will need to remove the Web push permission from the "Site Preferences" by going in the browser setting > History > Clear All History > select the time range "Everything" > tick Site Preferences > click on Clear Now.
You will need to proceed with the below steps in order to opt-out on Safari:
Go to your Safari settings and click on the Privacy tab then click on Manage Website Data..., wait for every sites' data to be loaded, select your domain and click on Remove:
You will then go to the Websites tab > Notifications > Select your domain > Click on Remove:
You'll need to go to the browser settings > click on the "privacy, search and services" tab> clear browsing data > click on choose what to clear > select the time range "All Time" > tick "Cookies and other site data" > click on Clear Now.
It will then be necessary to go in the "cookies and site permissions" tab > notifications > Click on the 3-dot-icon of the websites you want to opt-out from > Click Remove.