In my opinion, it is OK to start a sentence with also in a business context, as long as you use a comma. If in doubt, you could substitute another word like "Additionally," or say "I also" rather than "Also, I."

Also = in addition, too; Mice run very fast, cats do [also]. Boys like to eat Ice Cream, Girls do also. [Also] can be used to start a casual sentence depending on what you said before but for professional English or written English, it is not good practice to start a sentence with Also. ..... also, I wanted to tell you about our favorable new rates! or ......also, before I forget, can you bring back milk from the store?

Yes, you can start a sentence with "also" followed by a comma. Also, you can do the same with many of its synonyms: "besides", "moreover", "as well", and many more. As well, you can do the same with any conjunction so long as you follow it by a comma. And, you can do this in any context, even in a letter to the president of the Grammar Society.

Having problems with words is part of language-learning. Also, asking questions about them is something most of us do. (Linked to first sentence, like making a list).