Global Subscription Status field is not available when Marketing Automation feature is disabled. To enable the feature, perform the following steps:
1. Navigate to Setup > Company > Enable Features.
2. Click the CRM tab.
3. In the Basic Features section, check Marketing Automation.
4. Click I Agree.
5. Click Save.
Note: To default the Global Subscription Status field to Soft Opt-In, perform the following steps:
1. Navigate to Setup > Marketing > Marketing Preferences.
2. Uncheck Unsubscribed to Marketing By Default.
3. Click Save.