Assist Socially Disadvantaged and Veteran Farmers and Ranchers Act of 2018 This bill amends the Food, Agriculture, Conservation, and Trade Act of 1990 to reauthorize through FY2023 and modify the Department of Agriculture (USDA) Outreach and Assistance for Socially Disadvantaged Farmers and Ranchers and Veteran Farmers and Ranchers Program. (The program provides funding to assist socially disadvantaged and veteran farmers and ranchers in participating in USDA programs and in owning and operating farms and ranches.) The bill includes provisions that: authorize multiyear grants, contracts, and agreements for terms of up to three years; require USDA to establish an external peer review process to use in making grants and entering into contracts and agreements; and modify reporting requirements.