Why my inventory center is missing in 2019 Pro?

Hello there

I upgraded the system from 2016 to 2019 Pro, and the system updated the inventory items, and our sales invoice number. Everything went well except INVENTORY CENTER. 

The version 2016 that I use, it was "Inventory center" from vendors- inventory activities- inventory center, But for 2019 Pro, there is no Inventory center, which I need to use this feature on a daily basis. 

 I checked the products' information already  under Item List, (including the brand, size, and price, and quantities). That's fine. 

I read the blogs that she mentioned the verify Data, which I already did, but Nothing changed. 

From screenshot 3, " Learn More" which selections should I choose?

Screenshot 4, You could see my items & inventory from preferences "Enable" is grey. Please help.

PLEASE see attachments. 

Thanks