to hold up over one's head; to hold aloft
to hold over something; to hold (one's hands) out (e.g. towards a fire); to cover something with something
to hold up to shade one's eyes, face, etc.
傘をかざして日差しを遮った。
I held up an umbrella to block the sunlight.
手をかざして遠くを眺めた。
I shaded my eyes with my hand and gazed into the distance.
カードを読み取り機にかざす。
I hold the card up to the reader.