Quelle application dois-je sélectionner dans Adobe pour créer une grande affiche svp? Merci

Illustrator !

Is this project for print or digital screen output?

For print, use Illustrator or InDesign.  Before you start, consult your print professional about which settings to use.  Settings will vary based on the type of paper and ink that's used.

• https://99designs.com/blog/design-tutorials/create-typographic-poster-adobe-illustrator/
• https://www.adobe.com/products/indesign/poster-design-software.html

For digital screen output, you could use either Adobe Express (Spark page), Photoshop or Illustrator.

• https://www.adobe.com/express/create/poster
• https://helpx.adobe.com/photoshop/how-to/create-poster.html

Hope that helps.

My first inclination is to say Illustrator, as it has the best tools for more complex graphic effects. Depending on the details of the planned layout, InDesign could also be a good option.

Text-heavy work should not be done in Photoshop.