Use CloudConnector for Excel to call Wolfram Language functions from within spreadsheets.

Install Wolfram CloudConnector for Excel

Install the CloudConnector for Excel plugin by following the instructions in Setup and Getting Started.

Sign in to the Wolfram Cloud from Excel

From Excel, navigate to the Wolfram tab and select the Signed Out button to bring up the Wolfram Cloud dialog:

Call the Wolfram Function

Use the Wolfram function in Excel to call the Wolfram Language function RandomInteger: