how do you add text to a texture

[Meka Constantine]

trying to make a sign and don't remember how to add text to the texture

[Rolig Loon]

You make it while you are creating the texture in Photoshop or GIMP or whatever program you are using to make your textures.  Any image-processing software, even something as minimal as Powerpoint, has a text tool that lets you add text in whatever size, font, and color you choose, and then apply shading and other special effects if you want them.  When your texture is complete, save it as a TGA, PNG, JPG, or BMP file with appropriate "power of two" dimensions and upload it to SL.

If you have a background image that you want to be able to use separately from text in world, you can also use your image processing software to create a "texture" that has nothing but your text on it.  Again, Photoshop, GIMP, and the other programs (well, not Powerpoint) have tools that let you create text on a transparent background (a 32-bit image). Save that file, upload it, and put it on a second prim in front of your background image. You'll be able to move the text image around and superimpose it anywhere you like over the background.