Simply replace the unfilled areas such as "" and "[date]" with your information.
Dear [Hiring Manager],
As you know, I have been employed with [Company] for over [number] years. As this company has grown, I have had the opportunity to work with many employees. I feel confident that I am a good judge as to whether a candidate possesses the values and experience needed to succeed in this organization.
This is why I am recommending [Name] to you for your [position] position. [Name]'s qualifications include a [degree level] degree in [degree field] and [number] years experience in the [industry] industry at [Company]. I have become familiar with [his/her] through [location/activity]. I know [him/her] to be of excellent character. [He/She] is a [professional trait] individual and produces quality work.
[Name]'s resume is [enclosed/attached]. I have shared your contact information with [him/her] and [he/she] should be contacting you shortly.