一点and 有一点 are two different phrases with different meanings. They may be associated in a way if you look at the characters in them, but they don't mean the same thing at all and are used very differently

First, 有点 is actually the shortened version of 有一点

Before giving the "technical" explanations for 一点 and 有一点, I'd like to give you some examples in which each one is often used, in order to enable you to grasp a natural feeling about these two language elements.

For 一点：

（if you see the character“有” in these sentences, consider it as "have" or "there is", and note that it's entirely not the same as in the phrase "有一点"）

1. 我需要一点时间

I need a little time

2. 她每天都看一点书

She does some reading every day

3. 厨房里有一点食物

There is some food in the kitchen (perhaps not much)

4. 请喂它点水喝

Please feed it some water

5. 我需要放多少盐？- 一点就够了

How much salt do I need to add? - A small pinch will do

6. 有时人需要一点运气

Sometimes one just needs some luck

7. 可以再给我点咖啡吗？

Can I have some more coffee?/ Could you give me some more coffee?

8. 要有一点信念

Have some faith

9. 我只有一点钱

I only have very little money

10. 我从这个课程中只能学到一点知识

I can only learn very little knowledge from this course

11. 我一点钱也没有了

I don't have a single penny now

12. 我一点东西都不想吃

I don't want to eat anything at all

Feel free to linger on these sentences, read them out if you can, because it really helps

Now as you may have already found out, the phrase 一点 is very similar to "a little/some" in English, it indicates a small amount of something, especially uncountable things. It is way less often used to describe countable nouns(How do we describe a certain amount of something that is countable? Let me know if you wanna know). Usually, 一点 doesn't necessarily mean a very small amount, it can also mean "some". But if you want to clarify that you're talking about a really small amount, say 一点点. For example:

我这个天空的颜色对吗？- 再加一点点蓝色就好

Does the colour of my sky seem right? - You might want to add the least touch of blue

Moreover, it can sometimes be used to emphasize a really really small amount of something, perhaps not enough to do anything with it. In this case, the character "只" is usually used before it, as in sentences 9 and 10

Additionally, when it's used in a negative way, such as "一点……都不", it means none at all, as in sentences 11 and 12

Some useful variations of 一点:

(This is something useful and interesting but not necessary, so it's okay if you don't want to memorize the following explanations):

It is especially common to simplify 一点 as 点. Usually, they are completely interchangeable. If I must point out some difference, I would say "一点" sounds slightly more formal and sometimes with more emphasis, but not always. Hence, if you look at the sentences from 1 to 8, you can absolutely replace 一点 with 点 in every sentence, but NOT in sentences like from 9 to 12 (because in 9 to 12 "一点" means a little bit differently with more emphasis on the scarcity).

Also, people like to add a special sound after the character 点, it sounds like "er" in "mother" in American English. We use the character 儿 to stand for this sound. This is true for all circumstances, people speak with this sound all the time. From sentence 1 to 12, you can add the sound "er" in each one of them. You can hear what it sounds like in my voice messages in Tandem

So when you see things like 一点，一点儿，点，点儿, just remember they mean exactly the same thing and are often completely interchangeable in sentences like from 1 to 8

For example,

我需要一点时间

我需要一点儿时间

我需要点时间

我需要点儿时间

These four sentences mean exactly the same thing

For 有一点：

1. 天气有点热

It is kind of hot today

2. 我有一点冷

I'm feeling a little cold

3. 这道菜有一点咸

This course is a bit salty

4. 她男朋友有点坏

Her boyfriend is a bit mean

5. 我有打扰到你吗？- 有一点

Am I bothering you? - A little bit

6. 我今天有点不舒服

I'm not feeling very good today

7. 她有点难过

She's kind of sad

8. 我有点想辞职

I'm considering quitting my job

9. 今晚我有点想看电影

I wanna watch some movies tonight

10. 你是不是有点想睡觉？

Are you hoping to get some sleep?

11. 我有点不喜欢宠物

I don't really like pets very much

12. 我有点讨厌抽烟的人

I kind of hate people who smoke

有一点 indicates someone or something has certain attributes/emotion/intention to a limited extent or in a mild way. It works like an adverb in a sentence.

That also makes 有一点 become a very useful phrase to euphemistically express something or someone has some attributes/emotion/intention, even if it isn't mildly, we just say 有点 to sound less rude.

Note that the thing after 有一点 is usually something unpleasant or something that may cause troubles or bad influence. That's why we use 有一点 to say it in a euphemistic manner. Or it can also be used to convey a euphemistic request, showing that you want to do something. Or you can use it to say you're considering doing something but haven't made up your mind yet.

Variations:

Just remember that 有一点，有一点儿，有点，有点儿 all mean the same thing and are usually completely interchangeable

If you're trying to be euphemistic or polite, 有点 is absolutely more often used than 有一点(perhaps because it is less formal)

Let me know if you have further questions