I have set up alexa on my bose home speaker 300 and when using the voice command it automatically loads music via amazon music but id like it to do it using Spotify, is there a way to change this in the settings?
You can indeed change which music service Alexa will use by default on your speaker. This does need to be done through the Alexa app, as this is controlled your settings for Alexa there. How you would do this is by opening the menu in the Alexa app and navigating to Settings > Music and Media > Choose Default Music Service then selecting Spotify.
If Spotify does not show in that list automatically, you may need to link your Spotify account to your Alexa account but that can also be done from the Alexa app by going to Settings > Music & Podcasts > Link New Service.
Once you have done this, any time you ask Alexa to play music, she will prioritize using Spotify for this!