You can use one of the following methods to round values to 2 decimal places in Power BI:
Method 1: Use the decimal places feature in Column tools
Method 2: Use the ROUND function in DAX
The following examples show how to use each method in practice with the following table in Power BI:

Example 1: Round to 2 Decimal Places Using Column Tools
One way to round values in a column to 2 decimal places is to click the column name, then click the Column tools tab along the top, then type the value 2 into the decimal places box:

Notice that each value in the Avg Sales column is now rounded to 2 decimal places.
For example:
- 11.89343 has been rounded to 11.89.
- 12.2342 has been rounded to 12.23.
- 20.2009 has been rounded to 20.20.
And so on.
Example 2: Round to 2 Decimal Places Using DAX
Another way to round the values in a column to 2 decimal places is by using the ROUND function in DAX.
To do so, click the Table tools tab along the top and then click New column:

Then type the following formula into the formula bar:
Avg Sales Rounded = ROUND('my_data'[Avg Sales], 2)
This will create a new column named Avg Sales Rounded that rounds each value from the Avg Sales column to 2 decimal places:

Note #1: If any of the rounded values end in zero, the zeros will not be shown. For example, the value 15.0012 is rounded to 15.00, which is shown as just 15.
Note #2: You can find the complete documentation for the ROUND function in DAX here.
Additional Resources
The following tutorials explain how to perform other common tasks in Power BI:
How to Count Number of Occurrences in Power BI
How to Write an IF Statement in Power BI
How to Write an IF Statement with Multiple Conditions in Power BI