Registered Investment Advisors or RIAs sell direct plans of Mutual Funds while mutual fund distributors sell the regular plans. The portfolios of direct plan and regular plan both are absolutely the same. However, some fees or commission brings in the difference.
Investing through RIAs involves fees to be paid. This fees can be charged annually, monthly, per transaction, volume based, and so on. At times, individuals need to pay the fees to these RIAs even though they transact in mutual funds or not. Whereas, in regular funds there are no such commission chargers.
A regular plan of a Mutual Fund is the normal Mutual Fund scheme you buy from an intermediary such as a broker, financial advisor, distributor etc. In the regular plan, the asset management company pays commission to these intermediaries. That expense is recovered from the plan. Thus, regular Mutual Fund plans have higher expense ratios than the direct Mutual Fund plans.