Go to Edit > Define Pattern. Name your texture and click OK. Create a new, much larger document (e.g., 3000x3000px). Create a new Layer and go to Edit > Fill.
One of the most straightforward methods for creating a seamless texture in Photoshop is by using the Offset filter. This filter allows you to shift the image pixels, making it easy to create a tile that can be repeated seamlessly. To use the Offset filter, follow these steps: photoshop make seamless texture