It's not always possible to create your work at an angle that gives you perfectly straight lines. We ask that our members correct distorted perspectives before submitting assets to the queue.
If you've had assets sent back to straighten lines or fix skewed horizontal or vertical perspectives, here's how to do that in standard editing software:
This setting is called "Upright." You can find adobe's guidelines here.
On mobile, this setting is under "Geometry." You can find adobe's guidelines here.
The setting in Photoshop is "Perspective Warp." Adobe's guidelines can be found here.
In Capture One Pro, this is called "Keystone Correction." Guidelines can be found here.
Davinci Resolve has a "Lens Correction" tool. Their Manual includes more info (page 50).
Many mobile apps can straighten perspectives. Here are some the Artist Relations team have used and like: