Often times coaches will want to increase their knowledge of the game and pursue a certification track. While City League coaches are not required to be certified, rep (travel team) coaches are required to have up-to-date credentials for the season in which they coach.
The OLA chart linked here explains what certifications are required for coaches in the various age divisions. The OLA Coaching Pathway page explains how you go about achieving the certifications.
While City League coaches can, if they wish, to take the certification courses as a personal pursuit, but the club does not reimburses rec coaches for this, mainly because of the costs involved. Rep coaches usually are reimbursed by the rep team they are coaching.
Nevertheless, the OLA's Coaching page has material that should be of interest to all City League coaches.