Hello Jesus Aldana,

You can use default keyword while filed declaration to define default value.

For Ex:-

Here Some default value example for different type of field.

date = fields.Date('Date', default=lambda self: fields.datetime.now()) #Date Field

name = fields.Char('Name', default='New') #Char Field

type_selection = fields.Boolean('Type', default=True) #Boolean Field

Hope it will helps you.

Thanks,