why is my font in emails so small???

Hi, I'm Rodrigo, and I will help you.
To adjust the font size in this case, adjust the zoom level, hold CTRL and scroll up or down to adjust it.
CTRL and "+" or "-" works too

In Outlook, very small text in emails is usually caused either by the default font size being set too small for composing messages, or by the zoom level being reduced when reading or composing.

To fix outgoing and reply font size, adjust the default font settings:

1. In Outlook, open File > Options > Mail.
2. Select Stationery and Fonts.
3. Under New mail messages and Replying or forwarding messages, click Font.
4. In the Font dialog, increase the Size value (for example, to something like 11 or 12 pt), then select OK.
5. Select OK again to close the dialog and save changes.

If the text only looks small while reading messages (not actually saved small), increase the Reading Pane zoom:

1. In the Reading Pane, use the zoom slider at the bottom right to increase the percentage.
2. To apply the same zoom to all messages (classic Outlook): click the percentage value next to the slider to open the Zoom window.
3. Choose a zoom level, check Remember my preference, and select OK.

If the text is small while composing a message, adjust the compose zoom:

1. While composing, select Format > Zoom.
2. Choose a higher zoom percentage or enter a custom value.

These changes ensure both new messages and replies use a readable default font size, and that what is seen in the Reading Pane and compose window is not shrunk by zoom.

References:

• Change the default font or text color for email messages in Outlook
• Create, change, or customize a view in Outlook
• Use a screen reader to format text in your email in Outlook