Allow me to fill you in on everything about converting your QuickBooks Premier 2020 company file to QuickBooks Online (QBO).
When switching from QuickBooks Desktop to QBO, there are some limitations or causes you'll expect. Since you see invoices converted as journal entries, there may be a complication with recreating the original transaction. You'll want to read this link to know what to expect when importing your QuickBooks Desktop company file to QBO. Please know that the article is a US version, but it works the same as the other regions.