Yes, there are a number of training courses and development opportunities available to volunteers. The LTA run various training courses to support volunteers in their roles, such as the Competition Organiser course, First Aid training and Safeguarding workshops.
If you are a student aged 13+ at school, or in a college or university, you can enrol on a free Tennis Leaders course – to learn the core skills to begin volunteering in tennis.
Your County or tennis venue is likely to run further training, and it's worth discussing any training needs you may have. Club Matters, hosted by Sport England, have a range of workshops and online courses which support volunteers within sports clubs.