Fluent UI Textarea with Multiple Placeholders in SPFx

Microsoft Designer has a textarea for capturing prompt. It has a really nice interface for placeholders, where instead of a single placeholder text throughout, its a combination of static text and multiple placeholder text. I was not able to find a relevant control in Fluent UI library (assuming Microsoft Designer is based on Fluent UI and also the classes seems to be fluent UI classes)

How can above textarea be generated where its a combination of static text with multiple placeholder texts?