Laravel adding a role to a newly created user

Assuming you have these tables:

• users
• roles
• role_user

Where role_user has a role_id and a user_id column. Then your models would look something like:

class User extends Model
{

    /**
     * Roles relationship.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function roles(): BelongsToMany
    {
        return $this->belongsToMany(Role::class);
    }
}

class Role extends Model
{

    /**
     * Users relationship.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function users(): BelongsToMany
    {
        return $this->belongsToMany(User::class);
    }
}

And because it's a BelongsToMany relation, you would use the sync or syncWithoutDetaching methods to add or synchronise user roles. Or attach() for adding a single role to a user. For example:

// The $role variable can be a model instance, or an ID of the role.
$role = Role::all()->random();
$user = User::all()->random();

$user->roles()->syncWithoutDetaching($role);

// or
$user->roles()->attach($role);

I would recommend looking at the documentation for managing the relations (link). Because sync for example removes relations that aren't provided in the given array of models or ID's to synchronise - which would result in an unexpected behaviour if you aren't aware of this behaviour.