How I can export ALL activity and accounts to EXCEL?

There is no capability for exporting your entire data file to Excel from Quicken Mac. But you may be able to get there somewhat piecemeal.

What types of accounts do you have? Checking? Credit cards? Investments? Loans? Other? Does toy accountant need to see every transaction in every account, or just income and expenses, or account holdings, or …?

For all your non-investment accounts, there are two ways to approach this: a massive register dump, or a transaction report.

For the former:

• Click on Banking in the left sidebar. This create a register of all your banking (cash, checking, savings, credit card) accounts.
• Add any columns which might not currently be visible that you want, such as "Memo/Notes", Accounts, Transfer
• Set your date range to the period you want, such as This Year, Last Year or whatever date rang you want.
• Select File > Export > Register Transactions to CSV File
• Open the CVS file in Excel and do whatever clean-up/formatting you want

Note that each split line will be its own row in the Excel file, and denoted with an "S" in the Split column.

If you prefer to do this account by account, you'd just click on an account in the left sidebar and do the same thing.

The other way is to build a report and export it. Do this:

• Reports > New Report
• Transaction
• Rows=Category
• Create Report
• Click Customize
• Set your date range
• Add columns like Memo/Notes if useful
• Click Export > Export to CSV File

This gives you a report by Category, of course. And unlike the export above, this includes investment categories that create income, such as paid of reinvested dividends. If you want to do more with the data, you can select each Category and Fill Down to have the proper category in each row, so you can then sort by account or date or whatever you need.

If you need an export of the activities in your Investment categories

• Click on Investing in the left sidebar
• Click on the Transactions tab
• Set your date range
• Select File > Export > Register Transactions to CSV File
• Open the CVS file in Excel and do whatever clean-up/formatting you want

This may not be terribly useful without some formula-building in Excel, because the of the important details except cash flow are only in the Description column as text; you'd need to write formulas to parse out the number of shares, share price and value for these transactions. 

You can also switch to the Portfolio view and click Export, and select "Export With Lots to CSV" to create a file with all your investment transactions. You'd need to do some clean-up in Excel, and then sort by date to delete the stuff you don't need.

Bottom line: there's no one-stop export of all the types of transactions Quicken holds into Excel. Depending what information you need, though, you can likely extract it using one of these types of exports.