Smart Fill will detect patterns and make suggestions to help automate data entry. You can use Smart Fill for tasks like extracting the first name from a given list of full names or finding values in a range or table.
Smart Fill uses data in your sheet and knowledge available through Google’s public Knowledge Graph to detect patterns and generate suggestions.
A limited set of knowledge, such as capitals or stock tickers, is available through Google's public knowledge graph.Note: you may see enhanced Smart Fill suggestions 
if you are participating in the Workspace Labs program. Enhanced Smart Fill automatically detects the relationship between incomplete column pairs and uses AI to predict the remaining values, allowing them to be instantly filled. Learn more here.
Use Smart Fill
1. On your computer, open a spreadsheet in Google Sheets.
2. Enter data
- Mac: Press ⌘ + Shift + Y
- Windows/Chromebook: Ctrl + Shift + Y
Tip: Click a cell to see the formula used.
Turn off Smart Fill
1. On your computer, open a spreadsheet in Google Sheets.
2. At the top, click Tools 
3. Deselect Enable autocomplete.