You can set numeric value entries with specific limitation with following steps:

1. Select the range that you will set the numeric value entries, and click the Data > Data Validation. See screenshot:

2. In the opening Data Validation dialog box, go to the Setting tab, and:

(1) Select the Whole number item from the Allow drop down box. See the first screenshot below:
  
(2) Select one item from the Data drop down box according to your needs. See the second screenshot above:
(3) Input specific numbers for limitation in Maximum/Minimum/Length box according to your needs.

3. Click OK button.

This method is only able to set limitation for numeric values entered in cells. And the following method will guide you to set limitation for text entries.

If you have Kutools for Excel installed, you can apply its Prevent Typing feature to limit cell entry to numeric values, letters, or other special characters as you need, and also support to prevent from typing numeric numbers, letters, or specific characters in Excel.

Limit cell entry to whole numbers or decimal numbers only:

Prevent from typing letters in the specified range:

You can set limitation for text entries with following steps:

1. Preset all texts that other users can enter in cells, saying preset a list of name in A2:A10 as following screen shot show:

2. Select the range that you will set limitation for text entries in cells, and click the Data > Data Validation.

You can set limitation for text entries with following steps:

1. Preset all texts that other users can enter in cells, saying preset a list of name in A2:A10 as following screen shot show:

2. Select the range that you will set limitation for text entries in cells, and click the Data > Data Validation.

3. In the Data Validation dialog box, go to the Setting tab, and:
(1) Select the List item from the Allow drop down list;
(2) Check the In-cell dropdown option;
(3) Specify the preset source. In this case, it is the name list in A2:A10.

4. Click the OK button.

Then select one cell in the range with text entries limitation, it adds an arrow besides the active cell. Click the arrow , it shows a drop down list with preset name list. You can select one name to fill active cell easily. See screenshot below:


You can also set Input Message for numeric or text cell entries limitation, and set Error Alert for limitation as well.

Sometimes, you may be required to enter unique values in a column or a list. You can get it done with only one click by Kutools for Excel’s Prevent Duplicates utility.

Select the column or list that you will limit entering duplicates, and then click Kutools > Prevent Duplicates. From now on, when duplicate entries occur in the specified column or list, it will warn you immediately:

Easily Limit Cell Entry to Whole / Decimal Numbers Only in Excel