Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
To make the text appear larger, increase the text zoom. This can be done for emails that you are composing as well as for emails that you are reading (in the preview pane).
In a new email which is open in a separate window, go to the Format Text tab and click Zoom. In the dialog box, choose the value you prefer.
Similarly, to change the zoom in email messages that you are viewing, use the Zoom While Reading dialog box to set the preferred zoom. To display the dialog box, click the zoom control on the bottom right of your Outlook window.