How to make gradient colors into lines

Quick answer：

To create gradient colors that form lines, you can use graphic design software such as Adobe Photoshop or Illustrator. In Photoshop, you can create a gradient fill by selecting the Gradient Tool and choosing a linear or radial gradient. Then, draw a line with the Pen Tool or a Shape Tool and apply the gradient fill to it. In Illustrator, use the Gradient Mesh tool to create complex gradient lines. Both programs offer advanced customization options to adjust the gradient's direction, color stops, and blending modes.