Bulk SMS can be an effective way to inform supporters about your charity’s achievements and milestones. Here are the steps to follow:

1. Collect phone numbers: First, you need to collect the phone numbers of your supporters. Make sure you have their permission to contact them via SMS.
2. Choose a bulk SMS service: There are several bulk SMS services available online. Choose one that fits your needs and budget.
3. Compose your message: Keep your message brief and to the point. Highlight the achievement or milestone your charity has reached and how it has impacted your cause. Use language that inspires and motivates supporters to continue their support.
4. Personalize your message: Address your supporters by their name in the message. This will make them feel more connected to your charity.
5. Schedule your message: Choose a date and time when most of your supporters are likely to be available to receive the message.
6. Send the message: Once you have composed and scheduled your message, send it to your supporters.
7. Follow up: Follow up with your supporters to thank them for their continued support and encourage them to spread the word about your charity’s achievements.
   Remember to respect your supporters’ privacy and preferences. If they opt-out of receiving SMS messages, make sure you remove their phone number from your list. Also, avoid sending too many messages as it may lead to supporters feeling overwhelmed and opting-out.