Using Google Sheets to collaborate with others helps prevent people from entering the wrong data into the cells in your spreadsheet. Data validation prevents users from inserting data other than properly formatted data in specific areas. How to Use It:
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Using Data Review in Google Sheets
Start your browser and go to the Google Sheets home page Open A table and highlight the area you want to restrict.
Click Data, then Data Review.
In the Data Review window that appears, click the drop-down menu next to Criteria. Here you can specify a specific input type that takes into account the selected cells. For the selected line, we ensure that people enter a four-digit number for the year a movie was published. Therefore select the option "Number". You can also choose other criteria, such as: For example, only text, dates, a predefined list of options, items from the specified range, or your custom validation formula.
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Each option has its own values that you must specify for this function to validate data entered into each cell. Since we only want the year in which a movie was released, we use the "between" validation. Then we configure a minimum value of 1887 (the first video created) and a maximum of 2500, which should be sufficient for the requirements of this table.
Next, choose whether to show a warning message or completely deny all characters entered, and then display an error message if the data is invalid and keep the invalid data in the cell with a red notification.
If you choose "Reject input", the user will see a pop-up window. An inconspicuous error message after he submitted the invalid data and whatever he entered is also deleted.
You can also reject invalid submissions, but specify people with some feedback on the type of d ata required. Click Decline Input, select the check box for "Show help text for validation" and enter a helpful warning message. Click "Save" to close the validation tool.
If someone tries to enter invalid data, they will receive a helpful message so they can fix the error in their data. 
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Data validation is important if you want to gather information from people and make sure they have the right information in their records Enter table cells. It prevents someone from sending erroneous data and can be used as a catcher if you have set up formulas or automation tasks based on that data.