How to add/update picklist values in Salesforce

in order to add or update your current picklist in Salesforce, you would need to go through the below steps:

1. From Setup, click the Object Manager tab. If you don’t see the Object Manager tab, in the Quick Find box, enter Objects, and then select Objects.
2. Click the object name.
3. Click Fields & Relationships, and then click the name of the picklist field to update. In Salesforce Classic, in the Custom Fields & Relationships related list, click the name of the picklist field to update.
4. Add new or edit existing values: (1) In the Values section, click New or (2) Or in the Values section, click Edit.
5. Once you're done, don't forget to click on Save.