You define how time units are entered and displayed in the Units tab.
1. From the Tools menu, choose Options.
2. Click the Units tab.
3. Select the labels that you want to use for each time unit. These labels will be used for entering rates or for results. However, they are not used for entering duration. Duration units are defined in the Duration tab
4. Select the Add space before label check box to add a space between the data and label. For example, 5 days vs. 5days
5. Click the Set as Default button to set these as the default project settings
See also

Setting up calendar defaults

Setting up duration defaults

Setting up project management tool integration
Setting up your project defaults