Salesforce Fields are not visible to users on record page.

To resolve this issue, review the field accessibility of the profile assigned to the affected user. The following steps are grouped according to the profile user interface active in your org. To confirm if Enhanced Profile Interface is enabled or disabled, check the toggle for it under Setup | User Management Settings | Enhanced Profile User Interface.


If Enhanced Profile User Interface is enabled:

In Salesforce Classic
Setup | Manage Users | Users

1. Select the name of the user.
2. Select Profile.
3. Under Apps, select Object Settings, then select the object.
4. Click Edit.
5. Select Read box for the field they must see.
6. Save.

In Lightning Experience
Setup | Users | Users

1. Select the name of the user.
2. Select Profile.
3. Under Apps, click Object Settings, then select the object.
4. Under Field Permissions, click Edit.
5. Select the Read and Edit checkbox for the preferred fields they must see.
6. Save.

If Enhanced Profile User Interface is disabled:

1. Select the name of the user.
2. Select Profile.
3. Go to Field Level Security.
4. Click View on the object that must be modified.
5. Click Edit. 
6. Select Read and Edit checkbox for the field they must have access to.
7. Save.

Notes:

• Keep in mind that the changes affect all users assigned to the profile.  
• The deployment status on an object can also affect the ability to see the field. If the setting for an object is 'In Development' any lookup fields to that object will only appear to system administrators.

If the field accessibility is set to 'Visible' but the field is still not visible, check if the page assigned to the user is a dynamic record page. If it is, verify if there are any field visibility filters, and ensure that the affected user meets the criteria for those filters.

Refer this article for more information on field visibility criteria: https://developer.salesforce.com/files/accessibility/lightning_app_builder/add-visibility-rules-for-dynamic-pages-lab/index.html 

To see some additional helpful information that includes troubleshooting your user experience, watch Custom Field Not Showing Up Even Though it's In the Page Layout