This is Portuguese from Portugal. By default it would be default , or by default as we usually use in Brazil. It is the value that will be used in the absence of a certain value explicitly at the time it will be used.
So if it is MyISAM in most cases you want to use it is the most correct. If you almost always want to use InooDB then it would be interesting to change, but it is not required because you can always set the type at the time of creation.
In fact it is best to create new databases defined with engine that you want to use explicitly to avoid inconveniences of having changed the default without wanting or being in a different environment.
If you want to change go to the file my.cfg
and change:
[mysqld]
default-storage-engine = innodb