In order to create GIF image online you can use the programs like Picmonkey or Canva. These two are cloud applications and let you do image editing online. Most of the features which are found in popular applications like Adobe are also possible here.
In case of the offline application, you can create GIF image using Paint.NET or Photoshop or GIMP. These applications allow you to create GIF offline. Photoshop is a paid program. As GIMP and PAINT.Net are being free software, you don't pay for them.