There are many places to go for general coaching development, but I will keep it simple by sticking with two organizations.  The first one is U.S. Soccer as it is the governing body for soccer in America.  The second one is United Soccer Coaches as they too offer good training programs for coaches.  Both sites offer on-line and in-person classes that will help you to grow as a coach.  They also have many resources that accompany each class including practice plans.  If you need help deciding, I would go with U.S. Soccer.  

US Soccer

https://www.ussoccer.com

You can subscribe to US Soccer or else sign up for a class, which includes a subscription.   Once you get to the web site, click on the Coaching tab at the top and it will take you to the Learning Center where you can look at the classes offered.  Before you can take any of the classes though you must first complete the free intro course “Introduction to Grassroots Coaching”.  This is a free class and only takes about 20 minutes.  It serves as the pre-requisite all other classes.  They offer 4 on-line courses from 4v4 up to 11v11, which are based on the ages you coach ($25/ea.).   Some of these require accompanying on-line lessons in order to pass.  If you are interested in earning more advanced licenses, D, C, B, or A, you should check the prerequisites for each one.  These go in a progression and must be done in-person. 

United Soccer Coaches:

https://unitedsoccercoaches.org

This organization has a $125/year membership fee but you can also just take individual classes.  They also offer a free one-month subscription.  You can read more about the membership benefits on the web site.  Once you get to the website, click on Education and Master Course Schedule. They offer 3 On-Line classes at $20 each and like US Soccer, some good developmental programs based on age groups. They also have some other special topics classes, which are different from U.S. Soccer, but you can still do them on-line.  In addition, like US Soccer, they have an advanced diploma progression, which will require in-person classes.   

Our goal for the SWYSC is to provide consistent quality coaching appropriate for each age group.  We want our coaches to continue to learn and improve and in so doing we are able to provide challenge and growth for our players.   

My recommendations: 

All coaches: should watch the “Introduction to Grassroots Coaching” from US Soccer.  It doesn’t take much time and it lays out how we all should be coaching.  Then using the US Soccer offerings, complete the appropriate class listed

1. New Coaches:  in addition to #1 above, you should take the appropriate on-line class for the age group you will be working with as well as the one before it.  For example, if you are coaching age U-12, you should start at 7v7 and depending which organization got to 9v9.  This will provide you with a foundation for developing and running your practices.
2. Returning Coaches:  In addition to #1 above, I recommend you do the on-line class for your age group or if you want to strengthen your understanding follow the plan for new coaches.
3. Continuing Education:  For those who are serious about coaching, I recommend taking advanced license/diploma classes, when it is safe to do so.  These can take from 40 hours up to 180 of in-person and on-line learning and be quite a bit more expensive depending on the course, but if you envision coaching at higher levels, these will help.