I am not a native Portuguese speaker as our main supported language for community question is in English.
I will still try to answer your question but incase if you are not unable to understand English then can ask someone else in the team if they can speak Portuguese (but it might take time to answer back).
Regarding your question on changing logo, It is possible via configuration to do that but only supported with Grafana Enterprise or Cloud version.
For Grafana OSS there is no official guide as users are themselves responsible to change it by any method they like as it may get break in the next update release.
You can have a look at this post where other users asked same question and provided good instructions and links as how it can be done.