Angels are androgynous high spiritual beings. Intermediaries or messengers between God and humans. It doesn't matter if we prayer to God or the angels. The angels take the prayers to God. Angels exist is most religions and cultures of the world. Angels are mentioned more frequently in the Koran than there are in the Bible.
Angels exist on a much higher frequency than humans, which is normally beyond our range of hearing or sight. In the same way that we are unable to see x-rays or hear the high tones of a dog whistle.
They exist in the seventh dimension or the seventh heaven, as it is known.
They are on a different evolutional hierarchy than humans and in the majority of cases they have not incarnated as humans (i.e. have not gone through the physical birth process). There are some exceptions; Mother Mary (Queen of the Angels) and the prophets Enoch (Archangel Metatron) and Elijah (Archangel Sandalphon).
They may appear to a human in a variety of forms, usually so they do not frighten. Often they may appear in human form without wings. For example there are many stories of help arriving from nowhere when someone is stranded at night or someone is injured. Then they disappear afterwards without a trace.
People may sense them - see colours, smell pleasant odours, feel a draft of air or gentle touch or just have a sense there is something there. Some people are fortunate enough to see them, particularly in meditation.
Unlike humans they do not have free will. Their will is the Divine will. Therefore they are unable to assist us unless we request their help, but they are sometimes able to influence our thoughts and actions and can intervene in rare circumstances, for example in an accident, when it is not our time to pass over.
Since the angels are on a higher frequency than us, it is sometimes difficult for them to lower their vibration to meet ours. We must therefore help by raising our energies and increasing our light: being calm, relaxed, in nature, living a spiritual life, surrounding ourselves with pleasant objects, pictures, music and eating wholesome food etc. We can work at purifying our heart, bringing angelic qualities in to our lives: peace, love, compassion, harmony, forgiveness etc. When we visualise ourselves surrounded by gold and our auras being filled with golden light, the angels are able to draw closer to us.
There are many types of angels ready and willing to assist us. We each have a Guardian angel who stays with us through all lifetimes. We also have an angel assigned to this lifetime and for particular projects or episodes we might encounter. There are the mighty Archangels, such as Michael and Raphael, who can be called upon for protection or healing respectively. There are also angels of Peace, Prosperity and Singing etc. Thousands of angels are now drawing close to the Earth, as we move towards important spiritual times. We only have to ask, as them can only help us if we do so.