While there isn't a standard "text generator" built into a texture pack, you can achieve a "fullbright" effect for your text or world in Minecraft 1.12.2 using these methods: 1. The "Gamma" File Trick (No Pack Needed)
Conclusion
Q: Will this get me banned on Hypixel or Mineplex? A: Possibly. While it’s not X-ray, automated anti-cheat systems sometimes detect abnormal lightmap data. Use only on servers that explicitly allow visual modifications. minecraft 1.12.2 fullbright texture pack
Q: Will this lag my computer? A: No. In fact, it may slightly improve FPS because your GPU doesn't have to calculate as many shadow and light rendering engines. While there isn't a standard "text generator" built
Fullbright 1.12 by World Resource Pack : Hosted on Planet Minecraft, this version is optimized specifically for the 1.12 update and works best with OptiFine. How to Install Fullbright on Minecraft 1.12.2 GPU-side brightness shader (GLSL) for minimal CPU cost