No account is right for everyone. Three things decide which one fits you.
How you want the trade priced
On Standard there is no commission; its markup is in the spread: $1 a lot on currency pairs, and 50% of the spread on metals, indices and energy. On Raw and Pro you trade the liquidity provider's raw spread and pay a fixed commission per lot, charged once when the position opens: $7 on Raw, $5 on Pro. Spreads move with the market on every account. Compare the spreads of all three accounts and the commission, instrument by instrument, on the Fees page.
How much you will deposit first
The minimum first deposit is $5 on Standard, $5,000 on Raw and $20,000 on Pro.
How much leverage you need
You choose leverage when you open the account, from 1:1 up to the account maximum: 1:500 on Standard, 1:500 on Raw and 1:200 on Pro. Higher leverage means less margin per position, so the same equity can carry larger positions, and losses grow with them. See Leverage and margin.
Limits on every account
Each account can hold up to 2 lots open in one instrument, so the largest order is 2 lots. The cap is per instrument on each account, not a total for the account. You can hold up to 3 trading accounts.