The truth is that there is not yet a stable version compatible between the two major Minecraft tools, but if you really want to play with mods in version 1.14.4, there are some specific versions of forge and optifine that are compatible.

Compatible Versions:

• OptiFine_1.14.4_HD_U_F4
• forge-1.14.4-28.1.56-installer

How to Install Forge and Optifine?

1. First upgrade your Minecraft to 1.14.4.
2. Download the forge, go to the installer, proceed with the installation.
3. Open your Minecraft by selecting the installed forge profile.
4. Close Minecraft.
5. Go to start and open Run, look for: %appdata%\.Minecraft\mods
6. Download Optifine, and drag it into this folder (Mods).
7. Once you have done these steps open your Minecraft with the forge profile again, it should open with optifine installed.