Great questions - thank you! First, we'll address the question about prayer:
Matthew 6:6. But when you pray enter your inner room and close your door and pray to your Father who is in secret and your Father who sees in secret He will reward you in open. 7. And when you pray, you should not be chatterers like the pagans, for they hope that by many words they will be heard. 8. Therefore, do not imitate them for your Father knows what need you have before you ask Him. 9. Therefore, you pray like this: Our Father in heaven. Hallowed be thy name. 10. Thy Kingdom come. Thy will be done. As in heaven so on earth. 11 Give us the bread of our need this day. 12. And forgive us our offences as we also have forgiven those who have offended us. 13. And not bring us into trial, but deliver us from the evil one, for Yours is the Kingdom and the power and the glory forever and ever. (AENT)
Footnote: Prayer is a dialogue with Heaven, not a monologue. Y'shua's teaching stands as the demarcation between relationship with YHWH rather than a religion about Him. Prayer is meant to establish and maintain an intimate relationship, and accountability between each individual and YHWH.
The Bible doesn't command us to bow, fold hands, raise our hands, or kneel, although there is plenty of Scripture which mentions it. When the Disciples asked Yeshua to teach them how to pray, He didn't mention any folding of hands, etc., but simply said:
Luke 11: 1 One day Jesus was praying in a certain place. When he finished, one of his disciples said to him, "Lord, teach us to pray, just as John taught his disciples." 2He said to them, "When you pray, say: " 'Father, hallowed be your name, your kingdom come. 3 Give us each day our daily bread. 4 Forgive us our sins, for we also forgive everyone who sins against us. And lead us not into temptation.' "
There is no direct command in Scripture that says a person do anything at all when praying, which indicates that a believer can pray standing up, lying down or when walking - although kneeling in prayer is mentioned in the Bible many times:
1 Kings 8: 54 And it was so, that when Solomon had made an end of praying all this prayer and supplication unto the LORD, he arose from before the altar of the LORD, from kneeling on his knees with his hands spread up to heaven.
Psalm 95: 6 O come, let us worship and bow down: let us kneel before the LORD our maker.
Daniel 6: 10 Now when Daniel knew that the writing was signed, he went into his house; and his windows being open in his chamber toward Jerusalem, he kneeled upon his knees three times a day, and prayed, and gave thanks before his God, as he did aforetime.
Luke 22: 41 And he was withdrawn from them about a stone's cast, and kneeled down, and prayed.
Acts 9: 40 But Peter put them all forth, and kneeled down, and prayed...
Acts 20: 36 And when he (Paul) had thus spoken, he kneeled down, and prayed with them all.
Acts 21: 5 And when we had accomplished those days, we departed and went our way; and they all brought us on our way, with wives and children, till we were out of the city: and we kneeled down on the shore, and prayed.
Psalm 95 says: 1 Come, let us sing for joy to the LORD; let us shout aloud to the Rock of our salvation. 2 Let us come before him with thanksgiving and extol him with music and song. 3 For the LORD is the great God, the great King above all gods. 4 In his hand are the depths of the earth, and the mountain peaks belong to him. 5 The sea is his, for he made it, and his hands formed the dry land. 6 Come, let us bow down in worship, let us kneel before the LORD our Maker; 7 for he is our God and we are the people of his pasture, the flock under his care.
While Solomon was praying one day, he mentioned people praying with their bodies facing toward the temple (1 Kings 8:29-30, 35), toward Jerusalem (1 Kings 8:44), and Israel (1 Kings 8:48) whenever they were outside their homeland. In 2 Chronicles we note the following:
2 Chronicles 20: 18 Jehoshaphat bowed with his face to the ground, and all the people of Judah and Jerusalem fell down in worship before the LORD. 19 Then some Levites from the Kohathites and Korahites stood up and praised the LORD, the God of Israel, with very loud voice.
Yeshua "fell on his face and prayed" (Matt. 26:39). David and Nehemiah in the Tanach ("Old Testament") sat during prayer (Nehemiah 1:4-11; 1 Chronicles 17:16). Hannah prayed silently while her lips moved (1 Sam. 1:13). Ezra fell to his knees and stretched out holy hands to God (Ezra 9:5).
Solomon built a bronze platform from which he prayed (2 Chron. 6:13) while others fell on the ground (2 Chron. 20:18; Ezra 9:5; Matt. 26:39) and others went to the Lord's house (1 Chron. 17:16).
Does God prefer one prayer position over another? Who knows? Solomon said it was a matter of the heart:
1 Kings 8: 39 then hear from heaven, your dwelling place. Forgive and act; deal with each man according to all he does, since you know his heart (for you alone know the hearts of all men).