Use an online watermark remover tool (upload the image, apply removal, download the result)
Use Photoshop (open image, use Content-Aware Fill/Healing Brush/Clone Stamp to cover the watermark, save)
Use GIMP (open image, use Heal tool/Clone tool, carefully repaint over the watermark, export)
Use Snapseed (Tools → Healing, zoom in and remove the watermark area, export)
Use an AI editor with “remove object”/“erase” features (upload photo, select watermark region, apply, export)
If the watermark covers the subject heavily, crop the image to exclude the watermark area
Request a licensed, watermark-free version from the image owner or website
Use the original file/source where the watermark was not applied (download from the creator’s account or archive)