What are the pixel dimensions of your Photoshop document? Will it be printed, and if so, at what physical size in inches/cm?\
Also, your example image is missing important information: What is the magnification of that view? Because in any image editor (even outside Photoshop), magnifying beyond 100% (one image pixel to one display pixel) must always pixelate, because you are making each image pixel use more than one display pixel. This is true regardless of ppi or pixel dimensions.
If it’s a vector font in an EPS, it should be fully scalable, but in Photoshop, the hard limits to scalability are the pixel dimensions of the image. In other words, an image cannot resolve more detail than its pixel dimensions allow. That’s why others are advising you to enter the text in Illustrator or InDesign. Because those document formats are not pixel-based, any vector type in them will resolve to the full resolution of the output device.