In most cases, yes, you can enter a religious order without a college degree. Many communities, however, will strongly encourage you to get a degree either before entering the community or while you are in formation.
There are a couple of significant reasons why religious communities often prefer persons entering to have a college degree. First, education and college life are significant experiences that expand the doorways of one’s mind and one’s life experience. We discover new ideas and ways of relating with other people, God, and the world around us. We also learn a lot about ourselves. All of that is key to being in a good space to make a life commitment in a religious community.
Second, a college education is essential to discovering and becoming skilled in our talents and gifts. As a religious you will use this training well in whatever you do in your ministry and community life. Your education can help you in a particular ministry (e.g., social work, medicine, education, pastoral care) and it can help you with community responsibilities (e.g., administration, facilitation, interpersonal relationships, and so on).
Religious communities also recognize that a college education is not always possible due to personal finances or life circumstances. There is often room to work things out, especially if a person entering has had other life experience such as a full-time job.
Get to know the religious community you hope to join and talk with their vocation director to see what the possibilities are.