Proofread: I have solid accounting knowledge and training that (ALLOW OR ALLOWS) me to accomplish my responsibilities as an (Accounts Payable Clerk - sounds awkward, so there is probably an English title for this position.). Through my working experiences (no comma necessary here) I have acquired the skills to provide excellent customer service and to communicate with people from different backgrounds. I am highly proficient in Microsoft Excel, Word, Outlook, and (I - while it is correct and natural to say I twice, it is unnecessary and looks better in writing if you leave it out, it sounds just as natural and more professional to leave it out instead of mentioning it twice in one sentence.) have a strong understanding of (the - no 'the' necessary because of the word 'like' later on) accounting systems like Great Plains and QuickBooks. (In other words get rid of 'Like', or get rid of 'The' but don't have them together. ) Ex: I have a strong understanding of accounting systems like... I have a strong understanding of the account systems Great Plains and Quickbooks. Your paragraph overall is very good English. Except for the 'allowing' mistake, it reads just as good as a native English speaker but it can still be improved. So here is your paragraph with my corrections: I have solid accounting knowledge and training that allows me to accomplish my responsibilities as an accountant. Through my working experiences I have acquired the skills to provide excellent customer service and to communicate with people from different backgrounds. I am highly proficient in Microsoft Excel, Word, Outlook, and have a strong understanding of the accounting systems Great Plains and QuickBooks.

Not bad. Change "that allowing" to "that allow" in the first sentence. In the last sentence you should probably say "understanding of accounting systems" rather than "understanding of THE accounting systems". Or "understanding of the accounting systems Great Plains and QuickBooks". The word THE makes it specific. The word LIKE makes it general. Hope that helps.

thank you for all your help and replies

Alternatively, you could change the last passage like this: ... and I have a strong understanding of such accounting systems as Great Plains and QuickBooks.

I only suggest the 3 changes I've put in CAPITALS. I have solid accounting knowledge and training that ALLOW me to accomplish my responsibilities as an Accounts Payable Clerk. Through my working EXPERIENCE, I have acquired the skills to provide excellent customer service and to communicate with people from different backgrounds. I am highly proficient in Microsoft Excel, Word, Outlook, and I have a strong understanding of the accounting systems OF Great Plains and QuickBooks.