There are a lot of apps available for free to create attractive content for a platform like Instagram. Some of them are as follows:

Canva – has a collection of designs, templates, photos, icons – create whatever you want – resume, Instagram Story, slides, etc (free to use, some features cost if you don’t want a watermark on them)

PicsArt – basically it helps you go beyond the filter and touch-ups, very creative. Creators use it to for example easily change the background e.g. add clouds, sparkle, flames, etc.

For videos:

InShot – you can trim and cut video/movie, blur the background and no crop, add music and video effects. Also offers collage and photo EditorWorks on mobile (free to use, but offers in-app purchases).

Boomerang from Instagram – create captivating mini videos that loop back and forth (like a GIF) on mobile. Free to use.

Bonus app:
Buffer – This app can save your day! With Buffer, you can plan and publish your content not only for Instagram but for Facebook, Twitter, Pinterest, and LinkedIn, all from one simple dashboard. It saves time and helps to schedule your uploads. And it offers a free plan.

Hope this helps you out. Happy creating!