Now, as for recording your actual voicemail, you will be prompted to say and record your full name as this is the default voicemail of the Samsung Galaxy S9. If you would like to customize it instead to be a personalized message, follow these instructions.
Call Recorder Pro is a $9.99 one-time purchase, but offers only 300 minutes of calling credits; do an in-app purchase to record after that. Both offer "lite" versions to try out with limited record times (60 seconds) and features.

Phone call ring then voicemail sometimes and then goes right to voicemail no ring what does that mean phone off or ignoring call. I have metro pcs and my phone rings once then goes to voicemail when someone calls what could be the problem?
Professional voicemails are important, because they’re an extension of your personal brand, reflecting what level of professionalism you offer. Use these voicemail greetings for work or personal cell phone messages for your specific needs. You can choose a voice that will best suit your business and will deliver a warm and professional voice message. Your callers don’t want to hear a cold and indifferent machine voice. The information you want to put in your voicemail should be succinct enough for your callers to get every bit of information they need. Leave the relevant information in a clear and precise manner. Professional voicemail greetings for work should be informative. The first message the customer hears should have the company’s name so they can be sure they’ve reached the right number. Be courteous and informative. This could be their first point of contact, and you want it to be enjoyable. You may also like 30 Best Wishes and Congratulations for New Business Adventures If you’re going to make your voicemail message humorous in some way, it should be tasteful and aligned to your brand. It shouldn’t get in the way of giving customers enough information when they call. Your voicemail greetings for work should be welcoming and friendly but not too informal. Customers want to feel confident that they’ve contacted a professional, that the company values their call, and they have made the right choice. So be friendly but not too nonchalant. Your voicemail greeting should be clear, concise and to-the-point. You don’t have to put your clients through a sales pitch when they are trying to just get some information.