Open the formatting controls
In a chat or channel, expand the compose box with Format. Select the text and use the formatting toolbar. Microsoft documents bold, italic and underline controls along with additional options.
On mobile, its documented workflow starts with the plus button beside the compose box, then Format.
Choose message size
Microsoft’s message-size guide describes small, medium and large choices in the expanded composer’s Font size control. Choose the appropriate option while writing.
Treat the size as message formatting. It is not a font-file installation workflow or evidence that the recipient uses the same screen scale.
Use emphasis with clear wording
Compare a short announcement with a longer reply. Use headings, paragraphs and lists where they help the message. Keep the words themselves clear instead of relying only on color or a decorative alphabet.
Microsoft’s accessibility guidance recommends avoiding excessive capitalization and preserving meaning beyond color alone.
Choose the correct next workflow
For typography inside a presentation or workbook, edit the actual document using the PowerPoint guide or Excel guide.
An image of text can preserve its appearance, but ordinary editable message text remains more useful for selection and searching.
Your questions, answered.
Can I upload any font file into the Teams message toolbar?
The cited formatting workflow describes message styles and size choices, not arbitrary font-file uploads.
Where are the size choices?
Expand the composer with Format and use Font size. Microsoft lists small, medium and large for this workflow.
Sources & background
Sources supporting this page’s explanations. Practical examples are our editorial suggestions.