[pfd1986]

Does anyone know a good mockup for software? Say to show a client what a software would _look_ like and gather feedback?

[solardev]

Figma with templates / component libraries. Example for Material Design: https://www.figma.com/community/file/912837788133317724

Balsamiq for simpler wireframes

[open-source-ux]

Figma will fit the bill. You can find device mockups (free or paid) but you will need to edit the template. It's easy to share your mockup (with a URL) with colleagues or clients. They can also add comments to the mockup.

[Brajeshwar]

Do you mean static screens of your app? Try SceneShot for Mac, https://apps.apple.com/in/app/sceneshot/id1451459822

[njx]

https://www.mockuptiger.com/