Thank you for contacting Syncfusion support.
Based on the information provided, the ToolStripItems click events can be used to achieve your
requirement of "MiniToolBar with RichTextBox formatting" in WinForms.
We have prepared sample based on your requirement,
In the sample, we did the text formatting, bold, italic, underline and TextHighLight color according to your requirement.
We hope this helps. Please let us know, if you need any further assistance.
Subburaj Pandian V