Manage anonymous access for a web application in SharePoint Server
APPLIES TO: 
2013 2016 2019 Subscription Edition 
SharePoint in Microsoft 365
You can enable or disable anonymous access for a web application. If you enable anonymous access for a web application, site administrators can then grant or deny anonymous access at the site collection, site, or item level. If anonymous access is disabled for a web application, no sites within that web application can be accessed by anonymous users.
Note
Both classic and modern experience sites support anonymous access.
The following permission policies can be specified for anonymous users:
None: No policy is specified. This setting gives anonymous users the same default permissions available to NT AUTHORITY\Authenticated Users and All Authenticated Users.
Deny Write: This setting enables anonymous users to read all content within the site collections in a web application. You can then restrict the Read access by site collection, site, or item.
Deny All: Anonymous users have no access to any part of the web application.
Use the following procedure to configure anonymous access for a web application.
To configure anonymous access for a web application
Start SharePoint 2016 Central Administration.
On the SharePoint Central Administration website, in the Application Management section, click Manage web applications.
Click to highlight the web application whose permission policy that you want to manage.
In the Security group of the ribbon, click Authentication Providers.
Click the zone where you want to enable anonymous access.
Ensure that the Enable anonymous access check box is selected, and click OK.
In the Policy group of the ribbon, click Anonymous Policy.
In the Anonymous Access Restrictions dialog, in the ** Zone ** list, click the zone for which you want the policy to apply.
In the Permissions section, select the permission policy that you want anonymous users to have, and then click Save.