想 (xiǎng), 要 (yào) and 想要 (xiǎng yào) in Chinese are confusing to a lot of people, because they do mean similar things.
However, each one is used differently, so let’s clear up the differences
Use 要 (yào) when you are saying that you ‘want’ something physical or an object
我要一瓶啤酒
Wǒ yào yī píng píjiǔ
I want a bottle of beer.
我要那个
Wǒ yào nàge
I want that one.
In these situations, you can also use 想要 (xiǎng yào) ‘would like’, which is slightly ‘softer’
我想要一瓶啤酒
Wǒ xiǎng yào yī píng píjiǔ
I would like a bottle of beer.
我想要那个
Wǒ xiǎng yào nàge
I would like that one.
想 (xiǎng) is used with a verb to mean ‘want to do something’
我想吃饭 Wǒ xiǎng chīfàn – I want to eat.
我想喝茶 Wǒ xiǎng hē chá – I want to drink tea.
The character 想 contains the heart/mind radical, so its meaning is softer. It’s more like ‘desiring’ to do something.
In these situations you can also use 要 (yào), but it is stronger
我要吃饭 Wǒ yào chīfàn – I want to eat.
我要喝茶 Wǒ yào hē chá – I want to drink tea.
想 (xiǎng) can also be a verb, when followed by a noun, meaning ‘to miss’
我想你 Wǒ xiǎng nǐ – I miss you.
我想家 Wǒ xiǎng jiā – I miss home.
As well as meaning ‘want’, the character 要 (yào) has a few other uses that are worth knowing about.
要 (yào) can also mean ‘should’ or ‘need’ (obligation)
你要多喝水
Nǐ yào duō hē shuǐ
You should drink more water.
水果要先洗洗再吃
Shuǐguǒ yào xiān xǐxǐ zài chī
You should wash fruit first before eating it.
要 (yào) can also mean ‘will’ or ‘going to’ when talking about the near future
我明天要买书
Wǒ míngtiān yào mǎi shū
I am going to buy some books tomorrow.
他们要结婚
Tāmen yào jiéhūn
They are going to get married.
As well as meaning ‘not want’, 不要 (bù yào) can also mean ‘don’t’
不要说话
Bùyào shuō huà
Don’t talk
不要再喝了，你已经醉了
Bùyào zài hē le, nǐ yǐjīng zuì le
Don’t drink any more, you’re already drunk.